Illinois has a state estate tax with a relatively low threshold of $4 million — meaning many Illinois families with significant real estate or retirement assets may owe state estate tax even if they are well below the federal threshold. Understanding this distinction is critical for Illinois estate planning.
How Probate Works in Illinois
Illinois probate is filed in the Circuit Court of the county where the deceased lived (the Probate Division or Chancery Division, depending on the county). Illinois allows both independent administration and supervised administration. Independent administration is available when the will authorizes it, or when all heirs consent — it requires less court oversight and is generally faster and less expensive.
Cook County (Chicago) has the highest volume of probate cases in the state and can have significant scheduling backlogs. Collar counties and downstate courts generally move faster.
Small Estate Shortcuts in Illinois
If the gross probate estate is $100,000 or less, heirs can use a small estate affidavit to collect assets without opening formal probate. The affidavit must list all heirs and assets and be signed under oath. It can then be presented to banks, the DMV, and other institutions. No court filing is required.
This is one of the more useful small estate thresholds in the Midwest — $100,000 allows many modest estates to bypass probate entirely, particularly if the deceased's primary assets were in accounts with named beneficiaries.
Illinois State Estate Tax
Illinois levies a state estate tax on estates exceeding $4 million. The tax rates range from 0.8% to 16%, applied progressively to the taxable estate above the threshold. Illinois does not index its exemption for inflation, so its $4 million threshold has remained fixed while the federal exemption has grown to over $13 million — meaning many Illinois residents who face no federal estate tax owe significant state estate tax.
Illinois estate tax is due within 9 months of death and is filed with the Illinois Department of Revenue. A qualified estate planning attorney or CPA should be involved in any estate that approaches or exceeds the $4 million threshold.
How Long Does Probate Take in Illinois?
Illinois probate typically takes 9 to 18 months under independent administration. The 6-month creditor period begins at first publication and is a firm minimum. Cook County court backlogs can add 2–4 months to the initial filing and hearing schedule. Supervised administration in contested estates can extend the timeline significantly.
Executor Compensation
Illinois does not set a statutory executor fee. Compensation is based on reasonableness, considering the size and complexity of the estate. In practice, most Illinois executors receive 2–3% of the estate value. All compensation must be approved by the court or consented to by all beneficiaries. Attorney fees are similarly based on reasonable compensation.