Property tax in Boone County, Illinois
In Boone County, the property tax bill comes from the Boone County Treasurer. Every due date for the 2025 payable 2026 bill has passed, and the county had not posted the next cycle's dates when we checked. You can look up and pay the bill on the county's own payment page. Taken from Boone County's own pages, checked September 23, 2026.
The median property tax bill in Boone County, Illinois is $4,735 a year, which is about 2.18% of the county's median home value of $216,900. That effective rate is higher than the typical Illinois county (1.81%) and higher than the national median (0.81%). These are American Community Survey 5-year estimates (2024); your own bill depends on your home's assessed value and any exemptions.
Who sends the property tax bill in Boone County, and how do you pay it?
The bill comes from the Boone County Treasurer. The value it is based on is set by a separate office, the Boone County Supervisor of Assessments, with the township assessors, which is who to ask if the value looks wrong. For how to look up and pay the bill, go to the county's own payment information.
Township assessors value homes, and the county Supervisor of Assessments equalizes them. The exemptions on the county's pages (general homestead, senior, senior assessment freeze, disability, veterans, home improvement) and the senior tax deferral are the state's programs, applied for through the county. Illinois law makes no provision for partial payments. Most banks in the county take payments on the Treasurer's behalf, and there is an after-hours payment slot at the front of the building at 1212 Logan Avenue in Belvidere. Paying online by card or e-check adds a convenience fee of up to 2.5%, and the separate pay-by-phone line also charges a fee; the Treasurer's office itself does not take cards. Mobile homes get a separate bill, due May 4 in 2026.
When are property taxes due in Boone County?
Every due date for the 2025 payable 2026 bill has passed, and Boone County had not posted the next cycle's dates when we checked on September 23, 2026. If that bill is still unpaid, the late-payment rules below apply to it. Counties usually repeat the schedule, but confirm the new dates on your next bill. For the 2025 payable 2026 bill, Boone County splits the bill into 2 payments, the first due June 1, 2026 and the last September 1, 2026. A late installment is charged a 1.5% penalty the day after its due date, and the penalty grows by 1.5% each month until the tax is paid or sold. About two weeks after the deadline a delinquency notice goes out by certified mail with a $10 fee added, and delinquent parcels are published in the newspaper. Unpaid 2025 taxes are offered at the tax sale on Thursday, October 29, 2026; the Treasurer had not posted a last day to pay as of September 23, 2026. Taxes sold at the sale must be redeemed through the County Clerk with certified funds.
| Payment | Due | Note |
|---|---|---|
| First installment | June 1, 2026 (passed) | Bills for 2025 taxes were mailed May 1, 2026. You may pay both installments by June 1. A mailed payment must be postmarked on or before the due date. |
| Second installment | September 1, 2026 (passed) |
From Boone County's published schedule, checked September 23, 2026. If a date falls on a weekend or holiday, the county's own rules on the next business day apply.
Estimate the property tax on a home in Boone County
Enter a home's market value for a ballpark at Boone County's average effective rate of 2.18% (Census). The real bill depends on the home's assessed value, the millage where it sits and any exemptions.
Estimated property tax: $4,728 / year
Property tax in Boone County at a glance
| Measure | Value |
|---|---|
| Median annual property tax | $4,735 |
| Median home value | $216,900 |
| Effective tax rate | 2.18% |
| Typical Illinois county rate | 1.81% |
| National median county rate | 0.81% |
Effective rate = median real estate taxes paid divided by median home value. Source: U.S. Census Bureau, American Community Survey 5-year estimates.
How does Boone County compare in Illinois?
Among Illinois's 102 counties, Boone County has the 12th highest effective property-tax rate: 11 rank higher and 90 rank lower. That places it among the most heavily taxed counties in the state. Nationally, it ranks 49th of 3135 US counties by effective rate. See every Illinois county ranked.
How much do homeowners in Boone County actually pay?
The median is only the middle bill. Across Boone County's 15,915 owner-occupied homes, 73.6% pay $3,000 or more a year in property tax, 84.1% pay at least $2,000, and 6.6% pay under $800. Another 3.5% report paying no property tax at all, which usually means an exemption covers the whole bill.
| Annual bill | Homes | Share |
|---|---|---|
| Under $800 | 1,058 | 6.6% |
| $800 to $1,499 | 510 | 3.2% |
| $1,500 to $1,999 | 411 | 2.6% |
| $2,000 to $2,999 | 1,674 | 10.5% |
| $3,000 or more | 11,707 | 73.6% |
| No property tax paid | 555 | 3.5% |
Owners with a mortgage pay a median of $4,815 and owners without one pay $4,428. That is within 10% either way, so in Boone County paying off the house does not go with a noticeably different bill. Census table B25103.
How does the Boone County property tax bill compare with local incomes?
The median property tax bill of $4,735 is about 4.9% of the median income of Boone County homeowner households, $96,236 a year. That compares two middles, so a retiree in a long-held home can pay a far larger share. 81.8% of Boone County's occupied homes are lived in by their owners; renters pay property tax too, just folded into rent.
Have property taxes gone up in Boone County?
Yes. The median bill went from $3,930 in 2015-2019 to $4,735 in 2020-2024, a 20.5% rise. Over the same span the median home value moved 41.4%, from $153,400 to $216,900. Bills rose more slowly than values, which is what assessment caps and falling millage rates do: the county is taxing a smaller share of each home's worth.
Two Census ACS 5-year periods with no survey years in common, in each period's own dollars. A change counts only if it exceeds the combined 90% margin of error.
Property tax in counties next to Boone County
Boone County borders 6 counties, 2 of them across the state line.
| County | Effective rate | Median bill | Median home value |
|---|---|---|---|
| DeKalb County, IL | 2.45% | $5,974 | $243,600 |
| Winnebago County, IL | 2.39% | $3,930 | $164,500 |
| McHenry County, IL | 2.36% | $7,274 | $308,100 |
| Boone County, IL (this county) | 2.18% | $4,735 | $216,900 |
| Ogle County, IL | 2.06% | $3,889 | $189,200 |
| Rock County, WI | 1.6% | $3,703 | $231,600 |
| Walworth County, WI | 1.33% | $4,036 | $302,700 |
How is a home assessed in Boone County?
Illinois assesses homes at 33.33% of market value in every county, Boone County included. How Illinois assesses and reappraises homes.
Is there a homestead exemption in Boone County?
Yes. Illinois's General Homestead Exemption is $6,000 of equalized assessed value in most counties, $8,000 in counties next to Cook, and $10,000 in Cook County. That is the Illinois rule, and it applies in Boone County. Illinois's exemptions and relief programs in full.
Boone County does not add relief programs of its own beyond the Illinois ones (checked September 23, 2026).
How to appeal your Boone County property assessment
In Boone County you appeal to the Boone County Board of Review. The deadline: Within 30 days after your township's assessment changes are published in the newspaper. The county's overview page also says 'or by September 10, whichever is later', but current state law sets only the 30-day window, so count on 30 days. The Board of Review had not posted its 2026 publication dates or filing deadlines as of September 23, 2026. A Board of Review decision can be appealed to the Illinois Property Tax Appeal Board within 30 days of the written notice of the decision. How to file. Checked September 23, 2026 against state law, because Boone County does not restate them on its own pages.
How Illinois's appeal process works, including the next level if the first one turns you down.
Illinois rules from primary state sources, reviewed September 7, 2026; sources on the Illinois page.
Work out your own numbers
-
How much house can I afford?
Your income, debts and down payment against the 28/36 rule lenders actually use, with Boone County's tax rate to hand.
-
Mortgage calculator
Monthly payment with principal, interest, tax and insurance, plus what an extra payment saves you.
-
Illinois income tax
Brackets, standard deduction and what Illinois actually taxes.
-
Sales tax in Boone County
The other local tax: combined state and local rate for this county.
Sources
- Median real estate taxes paid and median home value for Boone County, Illinois: U.S. Census Bureau, American Community Survey 5-year estimates (2020-2024), tables B25103, B25077, B25102, B25119 and B25003; the five-year comparison uses the 2015-2019 estimates. Neighboring counties: Census county adjacency file.