Illinois Property Tax Rates by County: Complete 2026 Comparison

Complete Rate Comparison Table

All seven counties in the Chicago metro area served by Carlos Palomino at a glance. Rates are effective property tax rates — actual tax paid divided by market value.

Effective rates represent actual tax as a percentage of market value. Monthly escrow based on $300,000 home value. These are county-wide averages; individual parcels will vary.

Cook County — ~1.67% Effective Rate

Cook County has a lower effective rate than most collar counties, but this can be misleading. Cook uses a classified assessment system unique in Illinois: residential properties are assessed at 10% of market value rather than the state's 33.33% standard. This compressed taxable base produces lower-looking rates even when the underlying levy burden is substantial.

Within Cook County, rates vary enormously by township and municipality. Chicago city proper has different rates than suburban townships like Palatine, Schaumburg, or Orland. Properties in high-performing suburban school districts within Cook — Oak Park, Evanston, Wilmette — can carry effective rates approaching or exceeding 2.0% despite the county's lower average.

The Cook County Assessor's office completes reassessments on a triennial schedule, divided into three segments of the county. In reassessment years, assessments can shift dramatically. Buyers should always check the specific parcel's history and the most recent assessed value rather than relying on the seller's previous tax bill.

DuPage County — ~2.11% Effective Rate

DuPage County has a competitive rate among the collar counties and is widely regarded as one of the most desirable counties in Illinois for homeowners. It benefits from a relatively high median home value (around $355,000), a well-funded school system with strong performance outcomes, and a diversified commercial tax base that shares some of the levy burden.

Cities like Naperville, Wheaton, and Downers Grove sit in DuPage and command premium prices partly because buyers recognize that the combination of high home values and its effective rate produces a tax bill that is competitive with collar counties despite the higher price points.

DuPage County Township Assessors reassess properties every four years. The County Board of Review hears appeals filed within 30 days of the assessment notice mailing date for your township.

Will County — ~2.38% Effective Rate

Will County is one of the fastest-growing counties in the country, driven by suburban expansion south and southwest of Chicago. Cities like Joliet, Bolingbrook, Romeoville, Lockport, and New Lenox have seen significant residential development over the past two decades.

The ~2.38% effective rate reflects a common challenge in fast-growing areas: infrastructure and schools must scale rapidly to serve expanding populations, and that expansion is funded largely through property taxes. New subdivisions in Will County often carry rates that trail the county average in their first years but increase as taxing districts finalize levy calculations for newly populated areas.

Despite the higher rate, Will County offers some of the most affordable home prices in the Chicago metro area. The combination of lower prices and higher rates means the absolute dollar amount of tax may still be lower than DuPage County, even though the rate is higher.

Kane County — ~2.40% Effective Rate

Kane County, anchored by Aurora (Illinois' second-largest city) and Elgin, carries one of the higher effective rates among the collar counties. The county's tax burden is shaped by multiple high-cost school districts and the infrastructure needs of a geographically sprawling area.

Aurora itself spans two counties — both Kane and DuPage — and buyers should check which county a specific Aurora address falls in, as the tax implications differ substantially. In DuPage, rates are around 2.11%; in Kane, the same address category sits at approximately 2.40%.

Kane County's Township Assessors follow a four-year reassessment cycle. The Kane County Board of Review accepts appeals during a set window each year. The county's online GIS portal allows buyers to look up assessed values for any parcel before making an offer — a strongly recommended step.

Lake County — ~2.65% Effective Rate (Highest)

Lake County carries the highest effective property tax rate of the seven counties Carlos serves. This reflects a combination of factors: a large number of independent taxing bodies (school districts, park districts, fire protection districts, library districts, and more), high per-pupil school funding requirements, and a geographic spread that requires redundant infrastructure.

The irony is that Lake County is also one of the most desirable places to live in Illinois — Libertyville, Lake Forest, Highland Park, and Gurnee are all here. Buyers pay a premium for the amenities, but they pay again through property taxes. A $400,000 home in Lake County carries approximately $10,600 in annual property taxes — $883 per month in escrow alone.

Buyers in Lake County should aggressively research available exemptions and should not assume the previous owner's tax bill reflects what they will pay. Senior freeze exemptions and other reductions that were applied to the prior owner's bill will not automatically transfer.

McHenry County — ~2.56% Effective Rate

McHenry County, the northernmost of the collar counties and bordering Wisconsin, has seen steady suburban growth along the Route 47 and Route 31 corridors. Crystal Lake, Woodstock, and Algonquin are the population centers. Like Will County, the growth-driven demand for schools and services keeps the effective rate above 2.3%.

Home values in McHenry County are generally moderate, which means the absolute annual tax dollar amount is often competitive with other high-rate counties that carry higher home values. A $270,000 home at 2.56% generates $6,372 in annual taxes — comparable in absolute dollars to a similar-priced home in Kane County.

McHenry County uses a four-year reassessment cycle. The McHenry County Board of Review has an open appeal window that typically runs from October through November each year.

Kendall County — ~2.64% Effective Rate

Kendall County, located southwest of Chicago anchored by Yorkville and Oswego, experienced explosive growth in the 2000s that brought large new subdivisions and a rapidly expanding population. That growth outpaced the county's commercial tax base, placing an elevated levy burden on residential property.

Despite the high effective rate, Kendall County's median home values are among the most affordable in the metro area, making the absolute tax bill manageable for many buyers. Oswego's school district has a strong reputation, which attracts families willing to absorb the tax cost.

Kendall County's appeal process follows the standard Illinois four-year reassessment cycle with a County Board of Review appeal window. Because of the county's growth, assessment accuracy can sometimes lag — making appeals more likely to succeed for recently-built homes.

What Drives the Differences Between Counties

Why does Lake County charge almost twice what Cook County's classified system produces? Four factors explain most of the variation:

1. School District Funding

Illinois funds public schools primarily through property taxes rather than the state general fund. School levies typically account for 60–70% of a property's total tax bill. Counties with expensive-to-run school districts — high teacher salaries, newer facilities, more special programs — carry higher levies. Rural and outer-ring suburban counties that built new schools for growth populations in the 2000s are still paying off bond debt on those buildings.

2. Number and Fragmentation of Taxing Bodies

Illinois has over 6,900 units of local government — the most of any state. Each unit can levy taxes. A Lake County parcel might sit within a fire protection district, a library district, a park district, a mosquito abatement district, a water district, and a community college district on top of the city, township, county, and school district. Each adds a slice to the tax rate. Fragmented governance is expensive.

3. Commercial Tax Base

Counties with large commercial and industrial properties share the levy burden across more types of property. DuPage County benefits from substantial commercial development in Naperville and Downers Grove. Counties that are primarily residential — Kendall, McHenry — must cover their levy from homeowners' pockets alone.

4. Home Values vs. Levy Needs

Cook County's lower effective rate is partially explained by higher home values in many areas. When the aggregate value of all taxable property in a taxing district is high, the same levy amount translates to a lower rate per dollar of value. In areas where home values are moderate but government spending needs are high, the effective rate rises. Note: effective tax rates fluctuate annually based on assessments, equalization factors, and levy changes.

Impact on Monthly Payments: The Numbers That Matter

Here's the final comparison that matters most to a buyer: how much does your county choice affect your actual monthly payment at three different price points?

Monthly tax escrow = (home value × effective rate) ÷ 12. These amounts are added to principal, interest, and insurance in your total payment.

The difference between Cook County and Lake County on a $400,000 home is $327 per month — nearly $3,920 per year. That money does not build equity. It does not reduce your debt. It is a pure cost of location.

Use this data to have an honest conversation with yourself — and with Carlos — about whether a particular county's other benefits (schools, commute time, amenities) justify the tax premium. Sometimes they do. Sometimes the math says to look elsewhere.