Boone County, IL Property Tax: $4,507/yr (2026)
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The effective property tax rate in Boone County is 2.27% of assessed home value. On a home at the county median value of $198,600, that works out to about $4,508 per year, or $376 per month. Boone County is located in northern Illinois, with Belvidere as its county seat, and is home to approximately 53,316 residents.
About Boone County
Boone County covers approximately 280.7 square miles in Illinois. The county is home to about 53,316 residents living in roughly 20,238 housing units, of which 78.6% are owner-occupied. The median household income is $81,638, and the median home was built in 1981.
The county seat is Belvidere. Boone County borders DeKalb County, McHenry County, Ogle County, Winnebago County, Rock County — useful comparisons if you're considering nearby areas with potentially different tax rates.
How Property Taxes Work in Illinois
Property taxes in Illinois are administered at the county level. Each county sets a millage rate applied to the assessed value of real property — the effective rate above accounts for any partial assessments and exemptions already built into the local tax base. Assessed value can differ meaningfully from current market value depending on how often the county reassesses and what fraction of market value it uses.
Most counties in Illinois offer exemptions that reduce the taxable assessed value: homestead exemptions for primary residences, senior exemptions, disability exemptions, and veteran exemptions are common. These reduce your effective rate below the county-wide average shown here. Contact the Boone County Assessor's office to learn which exemptions apply to your property and when to file.
Boone County vs. Neighboring Counties
| Location | Eff. Rate | Median Home | Annual Tax |
|---|---|---|---|
| Boone County, IL | 2.27% | $198,600 | $4,508 |
| Illinois state average | 1.83% | — | $3,634* |
| DeKalb County | 2.54% | $231,900 | $5,889 |
| McHenry County | 2.49% | $286,900 | $7,153 |
| Ogle County | 2.03% | $184,100 | $3,737 |
| Winnebago County | 2.48% | $155,100 | $3,850 |
| Rock County | 1.69% | $215,900 | $3,652 |
| US national average | 1.10% | $281,900 | $3,101 |
*State average annual tax computed at Boone County's median home value of $198,600. Source: US Census ACS 2023 5-year estimates.
Frequently Asked Questions
How does Boone County's property tax rate compare to the rest of Illinois?
At 2.27%, Boone County is higher than the Illinois state average of 1.83%. On a home at the county median of $198,600, that means about $4,508 per year — versus $3,634 at the state average rate, a difference of $874 per year. Compared to the national average of 1.10%, Boone County is above average.
What's a typical annual property tax bill in Boone County?
For a home at the county median value of $198,600, the annual property tax in Boone County is approximately $4,508 — or about $376 per month. For a home worth $297,900, expect around $6,762 per year. For a $397,200 home, approximately $9,016 per year. Use the calculator above to estimate taxes for any assessed value.
Where do I appeal a Boone County property tax assessment?
Property assessment appeals in Boone County are handled by the Boone County Assessor's office in Belvidere. Most jurisdictions require filing within 30–90 days of receiving your assessment notice — confirm the specific deadline with the assessor's office before submitting, as deadlines and procedures vary by county. A successful appeal can reduce your assessed value and lower your tax bill for the current and future tax years.
What exemptions are available in Boone County?
Illinois counties commonly offer homestead exemptions for owner-occupied primary residences, senior citizen exemptions for qualifying homeowners aged 65 and older, exemptions for disabled residents, and veterans' exemptions. Each exemption reduces your assessed taxable value, which in turn reduces your effective tax rate below the county-wide 2.27% shown here. Contact the Boone County Assessor's office to confirm which exemptions are available and the application deadlines.
Data sources: US Census Bureau ACS 2023 5-Year Estimates, US Census Gazetteer (2024), County Adjacency File