Case brief
The reported NORTHWESTERN MEMORIAL HEALTHCARE incident at a glance
This summary is built from 35 public filings reported in Illinois. The earliest public notice date on record is September 1, 2025 and the latest is December 31, 2025. No incident date is stated in the public filing.
The information categories identified in the public filing are name, date of birth, social security number, medical record number, health insurance information, diagnosis and treatment information, prescription information, and contact information.
This site is not the official source for the filing. The links below point to the public attorney general or equivalent listings, and your own notification letter remains the source of truth for the details that apply to you.
Reported timeline
When the NORTHWESTERN MEMORIAL HEALTHCARE incident was reported
A chronological view of the dates stated in the public filing. Only dates actually reported are shown.
Earliest public notice
September 1, 2025
The earliest date a data breach notification was publicly reported by a state attorney general or equivalent office.
Latest public notice
December 31, 2025
The most recent date a data breach notification was publicly reported for this incident.
Public filing footprint
Where the NORTHWESTERN MEMORIAL HEALTHCARE notice was reported
NORTHWESTERN MEMORIAL HEALTHCARE is reflected in 35 public notification-letter listings reported in Illinois. Each listing is a separate public filing; together they describe the same reported incident from the perspective of the states that received a notice.
Illinois reported incident
A public Illinois notification-letter listing reports that NORTHWESTERN MEMORIAL HEALTHCARE sent a data breach notice or letter on September 1, 2025. The notice may identify name, date of birth, social security number, medical record number, health insurance information, diagnosis and treatment information, prescription information, and contact information as involved information.
- Notice reported
- September 1, 2025
- Incident date
- Not stated in the public listing
Illinois reported incident
A public Illinois notification-letter listing reports that NORTHWESTERN MEMORIAL HEALTHCARE sent a data breach notice or letter on September 3, 2025. The notice may identify name, date of birth, social security number, medical record number, health insurance information, diagnosis and treatment information, prescription information, and contact information as involved information.
- Notice reported
- September 3, 2025
- Incident date
- Not stated in the public listing
Illinois reported incident
A public Illinois notification-letter listing reports that NORTHWESTERN MEMORIAL HEALTHCARE sent a data breach notice or letter on September 4, 2025. The notice may identify name, date of birth, social security number, medical record number, health insurance information, diagnosis and treatment information, prescription information, and contact information as involved information.
- Notice reported
- September 4, 2025
- Incident date
- Not stated in the public listing
Illinois reported incident
A public Illinois notification-letter listing reports that NORTHWESTERN MEMORIAL HEALTHCARE sent a data breach notice or letter on September 8, 2025. The notice may identify name, date of birth, social security number, medical record number, health insurance information, diagnosis and treatment information, prescription information, and contact information as involved information.
- Notice reported
- September 8, 2025
- Incident date
- Not stated in the public listing
Illinois reported incident
A public Illinois notification-letter listing reports that NORTHWESTERN MEMORIAL HEALTHCARE sent a data breach notice or letter on September 9, 2025. The notice may identify name, date of birth, social security number, medical record number, health insurance information, diagnosis and treatment information, prescription information, and contact information as involved information.
- Notice reported
- September 9, 2025
- Incident date
- Not stated in the public listing
Illinois reported incident
A public Illinois notification-letter listing reports that NORTHWESTERN MEMORIAL HEALTHCARE sent a data breach notice or letter on September 10, 2025. The notice may identify name, date of birth, social security number, medical record number, health insurance information, diagnosis and treatment information, prescription information, and contact information as involved information.
- Notice reported
- September 10, 2025
- Incident date
- Not stated in the public listing
Illinois reported incident
A public Illinois notification-letter listing reports that NORTHWESTERN MEMORIAL HEALTHCARE sent a data breach notice or letter on September 19, 2025. The notice may identify name, date of birth, social security number, medical record number, health insurance information, diagnosis and treatment information, prescription information, and contact information as involved information.
- Notice reported
- September 19, 2025
- Incident date
- Not stated in the public listing
Illinois reported incident
A public Illinois notification-letter listing reports that NORTHWESTERN MEMORIAL HEALTHCARE sent a data breach notice or letter on September 24, 2025. The notice may identify name, date of birth, social security number, medical record number, health insurance information, diagnosis and treatment information, prescription information, and contact information as involved information.
- Notice reported
- September 24, 2025
- Incident date
- Not stated in the public listing
Illinois reported incident
A public Illinois notification-letter listing reports that NORTHWESTERN MEMORIAL HEALTHCARE sent a data breach notice or letter on October 1, 2025. The notice may identify name, date of birth, social security number, medical record number, health insurance information, diagnosis and treatment information, prescription information, and contact information as involved information.
- Notice reported
- October 1, 2025
- Incident date
- Not stated in the public listing
Illinois reported incident
A public Illinois notification-letter listing reports that NORTHWESTERN MEMORIAL HEALTHCARE sent a data breach notice or letter on October 3, 2025. The notice may identify name, date of birth, social security number, medical record number, health insurance information, diagnosis and treatment information, prescription information, and contact information as involved information.
- Notice reported
- October 3, 2025
- Incident date
- Not stated in the public listing
Illinois reported incident
A public Illinois notification-letter listing reports that NORTHWESTERN MEMORIAL HEALTHCARE sent a data breach notice or letter on October 7, 2025. The notice may identify name, date of birth, social security number, medical record number, health insurance information, diagnosis and treatment information, prescription information, and contact information as involved information.
- Notice reported
- October 7, 2025
- Incident date
- Not stated in the public listing
Illinois reported incident
A public Illinois notification-letter listing reports that NORTHWESTERN MEMORIAL HEALTHCARE sent a data breach notice or letter on October 8, 2025. The notice may identify name, date of birth, social security number, medical record number, health insurance information, diagnosis and treatment information, prescription information, and contact information as involved information.
- Notice reported
- October 8, 2025
- Incident date
- Not stated in the public listing
Illinois reported incident
A public Illinois notification-letter listing reports that NORTHWESTERN MEMORIAL HEALTHCARE sent a data breach notice or letter on October 9, 2025. The notice may identify name, date of birth, social security number, medical record number, health insurance information, diagnosis and treatment information, prescription information, and contact information as involved information.
- Notice reported
- October 9, 2025
- Incident date
- Not stated in the public listing
Illinois reported incident
A public Illinois notification-letter listing reports that NORTHWESTERN MEMORIAL HEALTHCARE sent a data breach notice or letter on October 13, 2025. The notice may identify name, date of birth, social security number, medical record number, health insurance information, diagnosis and treatment information, prescription information, and contact information as involved information.
- Notice reported
- October 13, 2025
- Incident date
- Not stated in the public listing
Illinois reported incident
A public Illinois notification-letter listing reports that NORTHWESTERN MEMORIAL HEALTHCARE sent a data breach notice or letter on October 15, 2025. The notice may identify name, date of birth, social security number, medical record number, health insurance information, diagnosis and treatment information, prescription information, and contact information as involved information.
- Notice reported
- October 15, 2025
- Incident date
- Not stated in the public listing
Illinois reported incident
A public Illinois notification-letter listing reports that NORTHWESTERN MEMORIAL HEALTHCARE sent a data breach notice or letter on October 23, 2025. The notice may identify name, date of birth, social security number, medical record number, health insurance information, diagnosis and treatment information, prescription information, and contact information as involved information.
- Notice reported
- October 23, 2025
- Incident date
- Not stated in the public listing
Illinois reported incident
A public Illinois notification-letter listing reports that NORTHWESTERN MEMORIAL HEALTHCARE sent a data breach notice or letter on October 24, 2025. The notice may identify name, date of birth, social security number, medical record number, health insurance information, diagnosis and treatment information, prescription information, and contact information as involved information.
- Notice reported
- October 24, 2025
- Incident date
- Not stated in the public listing
Illinois reported incident
A public Illinois notification-letter listing reports that NORTHWESTERN MEMORIAL HEALTHCARE sent a data breach notice or letter on October 27, 2025. The notice may identify name, date of birth, social security number, medical record number, health insurance information, diagnosis and treatment information, prescription information, and contact information as involved information.
- Notice reported
- October 27, 2025
- Incident date
- Not stated in the public listing
Illinois reported incident
A public Illinois notification-letter listing reports that NORTHWESTERN MEMORIAL HEALTHCARE sent a data breach notice or letter on October 28, 2025. The notice may identify name, date of birth, social security number, medical record number, health insurance information, diagnosis and treatment information, prescription information, and contact information as involved information.
- Notice reported
- October 28, 2025
- Incident date
- Not stated in the public listing
Illinois reported incident
A public Illinois notification-letter listing reports that NORTHWESTERN MEMORIAL HEALTHCARE sent a data breach notice or letter on November 5, 2025. The notice may identify name, date of birth, social security number, medical record number, health insurance information, diagnosis and treatment information, prescription information, and contact information as involved information.
- Notice reported
- November 5, 2025
- Incident date
- Not stated in the public listing
Illinois reported incident
A public Illinois notification-letter listing reports that NORTHWESTERN MEMORIAL HEALTHCARE sent a data breach notice or letter on November 8, 2025. The notice may identify name, date of birth, social security number, medical record number, health insurance information, diagnosis and treatment information, prescription information, and contact information as involved information.
- Notice reported
- November 8, 2025
- Incident date
- Not stated in the public listing
Illinois reported incident
A public Illinois notification-letter listing reports that NORTHWESTERN MEMORIAL HEALTHCARE sent a data breach notice or letter on November 13, 2025. The notice may identify name, date of birth, social security number, medical record number, health insurance information, diagnosis and treatment information, prescription information, and contact information as involved information.
- Notice reported
- November 13, 2025
- Incident date
- Not stated in the public listing
Illinois reported incident
A public Illinois notification-letter listing reports that NORTHWESTERN MEMORIAL HEALTHCARE sent a data breach notice or letter on November 17, 2025. The notice may identify name, date of birth, social security number, medical record number, health insurance information, diagnosis and treatment information, prescription information, and contact information as involved information.
- Notice reported
- November 17, 2025
- Incident date
- Not stated in the public listing
Illinois reported incident
A public Illinois notification-letter listing reports that NORTHWESTERN MEMORIAL HEALTHCARE sent a data breach notice or letter on November 18, 2025. The notice may identify name, date of birth, social security number, medical record number, health insurance information, diagnosis and treatment information, prescription information, and contact information as involved information.
- Notice reported
- November 18, 2025
- Incident date
- Not stated in the public listing
Illinois reported incident
A public Illinois notification-letter listing reports that NORTHWESTERN MEMORIAL HEALTHCARE sent a data breach notice or letter on November 20, 2025. The notice may identify name, date of birth, social security number, medical record number, health insurance information, diagnosis and treatment information, prescription information, and contact information as involved information.
- Notice reported
- November 20, 2025
- Incident date
- Not stated in the public listing
Illinois reported incident
A public Illinois notification-letter listing reports that NORTHWESTERN MEMORIAL HEALTHCARE sent a data breach notice or letter on December 1, 2025. The notice may identify name, date of birth, social security number, medical record number, health insurance information, diagnosis and treatment information, prescription information, and contact information as involved information.
- Notice reported
- December 1, 2025
- Incident date
- Not stated in the public listing
Illinois reported incident
A public Illinois notification-letter listing reports that NORTHWESTERN MEMORIAL HEALTHCARE sent a data breach notice or letter on December 2, 2025. The notice may identify name, date of birth, social security number, medical record number, health insurance information, diagnosis and treatment information, prescription information, and contact information as involved information.
- Notice reported
- December 2, 2025
- Incident date
- Not stated in the public listing
Illinois reported incident
A public Illinois notification-letter listing reports that NORTHWESTERN MEMORIAL HEALTHCARE sent a data breach notice or letter on December 4, 2025. The notice may identify name, date of birth, social security number, medical record number, health insurance information, diagnosis and treatment information, prescription information, and contact information as involved information.
- Notice reported
- December 4, 2025
- Incident date
- Not stated in the public listing
Illinois reported incident
A public Illinois notification-letter listing reports that NORTHWESTERN MEMORIAL HEALTHCARE sent a data breach notice or letter on December 7, 2025. The notice may identify name, date of birth, social security number, medical record number, health insurance information, diagnosis and treatment information, prescription information, and contact information as involved information.
- Notice reported
- December 7, 2025
- Incident date
- Not stated in the public listing
Illinois reported incident
A public Illinois notification-letter listing reports that NORTHWESTERN MEMORIAL HEALTHCARE sent a data breach notice or letter on December 8, 2025. The notice may identify name, date of birth, social security number, medical record number, health insurance information, diagnosis and treatment information, prescription information, and contact information as involved information.
- Notice reported
- December 8, 2025
- Incident date
- Not stated in the public listing
Illinois reported incident
A public Illinois notification-letter listing reports that NORTHWESTERN MEMORIAL HEALTHCARE sent a data breach notice or letter on December 17, 2025. The notice may identify name, date of birth, social security number, medical record number, health insurance information, diagnosis and treatment information, prescription information, and contact information as involved information.
- Notice reported
- December 17, 2025
- Incident date
- Not stated in the public listing
Illinois reported incident
A public Illinois notification-letter listing reports that NORTHWESTERN MEMORIAL HEALTHCARE sent a data breach notice or letter on December 21, 2025. The notice may identify name, date of birth, social security number, medical record number, health insurance information, diagnosis and treatment information, prescription information, and contact information as involved information.
- Notice reported
- December 21, 2025
- Incident date
- Not stated in the public listing
Illinois reported incident
A public Illinois notification-letter listing reports that NORTHWESTERN MEMORIAL HEALTHCARE sent a data breach notice or letter on December 23, 2025. The notice may identify name, date of birth, social security number, medical record number, health insurance information, diagnosis and treatment information, prescription information, and contact information as involved information.
- Notice reported
- December 23, 2025
- Incident date
- Not stated in the public listing
Illinois reported incident
A public Illinois notification-letter listing reports that NORTHWESTERN MEMORIAL HEALTHCARE sent a data breach notice or letter on December 29, 2025. The notice may identify name, date of birth, social security number, medical record number, health insurance information, diagnosis and treatment information, prescription information, and contact information as involved information.
- Notice reported
- December 29, 2025
- Incident date
- Not stated in the public listing
Illinois reported incident
A public Illinois notification-letter listing reports that NORTHWESTERN MEMORIAL HEALTHCARE sent a data breach notice or letter on December 31, 2025. The notice may identify name, date of birth, social security number, medical record number, health insurance information, diagnosis and treatment information, prescription information, and contact information as involved information.
- Notice reported
- December 31, 2025
- Incident date
- Not stated in the public listing
Practical considerations
What to do based on the reported NORTHWESTERN MEMORIAL HEALTHCARE details
These steps are tailored to the information actually present in the public filing for this incident.
- The public filing names name, date of birth, social security number, medical record number, health insurance information, diagnosis and treatment information, prescription information, and contact information as information that may be involved. Review your own letter for these categories and note exactly which of your information is listed.
- Because the identified categories may include sensitive details, consider placing a security freeze or fraud alert with the major credit bureaus and watching for unusual account activity.
- The public filing does not state when the incident occurred. The date in your own letter is your best reference for the timeframe to monitor.
- Notices were publicly reported between September 1, 2025 and December 31, 2025. If your letter lists an enrollment deadline for credit monitoring, track it from the date on your notice, not from these public reporting dates.
- Keep your original letter in a safe place. Do not rely on a link or phone number in the notice until you have independently verified it through an official website or an account statement you already trust.
Action plan
What to do with this NORTHWESTERN MEMORIAL HEALTHCARE notice
These steps are drawn from the public filing facts above. They describe the public record; your own letter is the source of truth for the deadlines, offers, and information that apply to you. No step here assumes that NORTHWESTERN MEMORIAL HEALTHCARE offers monitoring, credit protection, or compensation.
Save your letter and its key dates
Keep the original notice, envelope, and any emails together in a safe place. Note every date the letter lists, such as the incident date, any enrollment deadline, or a response cutoff. For context, The public filing does not state when the incident occurred, and public notices were reported between September 1, 2025 and December 31, 2025. The dates printed on your own letter are the ones that apply to you.
Review the information categories involved
The public filing identifies name, date of birth, social security number, medical record number, health insurance information, diagnosis and treatment information, prescription information, and contact information as information that may be involved. Compare this with the data section of your own letter and note exactly which of your information is listed. Because the identified categories may include sensitive details, take the protective steps below seriously.
Verify any monitoring offer before enrolling
Your own letter, not the public filing, will state whether free credit or identity monitoring is offered to you, what it covers, and its enrollment deadline. Before using any link, phone number, or enrollment code in the notice, confirm the letter is genuine by contacting the company through a website or statement you already trust.
Protect your accounts and credit
Because the filing identifies information that may include sensitive details, consider placing a free security freeze with each major credit bureau and watch relevant financial and account activity for anything unfamiliar. A freeze is free and does not affect your existing accounts.
Law Office of David S. Harris
Received a NORTHWESTERN MEMORIAL HEALTHCARE breach notice?
A NORTHWESTERN MEMORIAL HEALTHCARE data breach notice is a notification of potential exposure, not confirmation that a lawsuit has been filed, that you automatically qualify, or that compensation is available. Whether a class action, individual claim, or settlement opportunity may ever apply depends on the specific facts, the information involved, the law, and any court-approved terms. If you would like to understand your options, request a confidential review with the Law Office of David S. Harris. No fee unless you recover.
Verify before you respond
Is this NORTHWESTERN MEMORIAL HEALTHCARE breach notice real?
The reported incident details above can help confirm that an incident was publicly listed. Still, verify the letter itself before using any link, phone number, or attachment in it. Find NORTHWESTERN MEMORIAL HEALTHCARE's official website independently, use contact information from a statement or account you already trust, and ask whether the notice was sent to you.
Learn how to spot a legitimate noticeRelated resources
Guidance for your NORTHWESTERN MEMORIAL HEALTHCARE notification letter
Use these practical guides to verify a notice, understand what it may mean, and take the next steps after a reported data breach.
Keep exploring
More Illinois data breach notice guides
If you received a letter from another organization, review its guide here. Each link keeps you on this site and leads to another reported incident summary.