Which county has the highest property taxes? (2025 edition)

County property taxes are measured in mills — with 1 mill equaling $1 in tax for every $1,000 of assessed value. But each county assesses property differently, largely based on how long it's been since the most recent comprehensive, countywide reassessment.

That assessment calculation is based on the common level ratio (CLR), which is set annually for each county by the state.

For example, in Bucks County, the CLR Factor is 15.87, which means the assessed value of a property should be about 1/15.87th (or 6.3%) of its market value. For a $300,000 home, that means an assessment of about $18,900. The millage rate in Bucks is 27.45, so the tax = 18.9 x 27.45 = $519. 

The chart below incorporates assessment ratios and millage rates to give an approximate comparison of the taxes each county would charge on a home with a market value of about $300,000.