How to get appointed administrator of your sister’s estate in Illinois when she died without a will

Short answer: If your sister died intestate (without a will) in Illinois, a probate court in the county where she lived can appoint a personal representative (often called an administrator or administrator of an intestate estate). You (or another heir) must file a petition with the local circuit court probate division, notify interested persons, and—if the court approves—receive letters of office after taking an oath and meeting bond requirements (unless waived). This article explains the typical steps, the legal framework, and practical tips so you know what to expect.

Detailed answer — step by step under Illinois law

1. Confirm there is no valid will and whether probate is needed

First, make sure your sister left no valid will. If she did, the person named as executor would normally apply for appointment. If there is truly no will (intestacy), the estate passes under Illinois intestate succession rules and the court appoints an administrator. The relevant statutory framework is the Illinois Probate Act of 1975 (commonly cited as 755 ILCS 5/). See the Probate Act here: https://www.ilga.gov/legislation/ilcs/ilcs3.asp?ActID=2100&ChapterID=60.

2. Determine the correct court

File in the circuit court (probate division) for the county where your sister was domiciled when she died. Use the Illinois courts site to find the correct circuit court: https://www.illinoiscourts.gov/find-a-court/.

3. Who can be appointed?

The court prefers to appoint a person with the highest statutory priority who is willing and qualified to serve. Priority generally follows the persons who inherit under the intestacy rules (for example: surviving spouse, children, parents, siblings, etc.). If siblings are the highest-priority heirs, a sibling who petitions may be appointed. The Probate Act governs priority and appointment procedures; consult the Act for details: https://www.ilga.gov/legislation/ilcs/ilcs3.asp?ActID=2100&ChapterID=60.

4. File a petition for letters of administration

Common documents you will file or bring to the court clerk include:

A petition for letters of administration (sometimes called petition for appointment of personal representative)
An official copy of the death certificate
A proposed order and letters form (the court provides forms or local templates)
Information about heirs and potential creditors (names, addresses, and relationship)

The clerk can tell you the local filing fee and whether the county has a standard form. If you are not sure what to include, the clerk can often provide general guidance about filing requirements (not legal advice).

5. Notice, hearing, and objections

After you file, the court will set a hearing and require notice to interested persons (heirs, next of kin). If no one objects and the petitioner is qualified, the court usually appoints the petitioner. If someone objects or multiple people claim priority, the court will decide who should serve.

6. Bond and oath

Before issuing letters of administration the court will require the administrator to take an oath. The court often requires a surety bond to protect the estate, although heirs may be able to waive or reduce bond if the law or the court allows and other heirs agree. The Probate Act contains rules about bonds and waivers: https://www.ilga.gov/legislation/ilcs/ilcs3.asp?ActID=2100&ChapterID=60.

7. Letters of office and duties after appointment

Once appointed, the court issues letters of office (letters of administration). As administrator you must marshal and safeguard estate assets, notify and pay creditors, prepare inventories and accountings when required, file tax returns, and distribute assets to heirs under Illinois intestacy rules. Keep careful records; the court may require periodic reports and a final accounting.

8. Small or simplified procedures

If the estate is very small or contains only certain types of property, Illinois offers simplified procedures in some situations (for example, small-claims or affidavit transfers). Whether a simplified route applies depends on the estate’s assets and the type of property. Ask the probate clerk or an attorney whether a small-estate procedure applies.

9. Practical timeline

Timelines vary. Initial appointment steps—from filing to appointment—often take a few weeks to a few months depending on court workload and whether there are objections. After appointment, administration time depends on estate complexity, creditor claims, and tax matters. Complex estates can take a year or more; simple estates can close in months.

Statutes and official resources

Illinois Probate Act of 1975 (general reference): https://www.ilga.gov/legislation/ilcs/ilcs3.asp?ActID=2100&ChapterID=60
Find your county circuit court (probate division) and local court contact info: https://www.illinoiscourts.gov/find-a-court/

Helpful hints

Get multiple certified copies of the death certificate early. Many institutions require originals or certified copies.
Gather proof of relationship (birth certificates, family records) to show you are an heir if the court asks.
Prepare a simple list of known assets (bank accounts, real estate, vehicles, safe-deposit boxes, life insurance) and debts. This speeds the initial filing and later administration steps.
Talk with the probate clerk before filing. Clerks can explain local forms, fees, and hearing schedules but cannot give legal advice.
If other heirs exist, ask whether they will sign a bond waiver. A bond waiver can simplify the appointment and save money.
Keep detailed records (receipts, notices, bank statements). Courts expect orderly records and accountings from administrators.
Consider whether a simplified or small-estate procedure applies. That can avoid full probate if the estate qualifies.
If disagreements arise among heirs or the estate has unusual assets (business interests, out-of-state property, or contested claims), consult a probate attorney.
Expect to notify creditors and publish notice where required. Failing to give required notice can affect distribution and liability.

When to get legal help

Consider hiring a probate attorney if you face contested priority for appointment, complex assets, creditor claims, tax issues, disputes among heirs, or if you prefer help preparing court documents and filings. If the estate is straightforward and all heirs agree, many people successfully proceed without an attorney by working with the probate clerk and following court forms and instructions.

Disclaimer

This article is informational and does not provide legal advice. It summarizes general Illinois probate procedures; it does not address every situation. For advice about your specific circumstances, speak with a licensed Illinois attorney or the probate court clerk where the decedent lived.