Illinois and Kentucky at a glance
Illinois and Kentucky share a border, but a paycheck does not travel across it unchanged. A $60,000 salary leaves $22,627 a year after taxes and the four basics in Illinois and $29,937 in Kentucky.
Kentucky comes out ahead by $7,310 a year ($609 a month). The calculation starts from the same gross pay in both states, subtracts federal tax, Social Security and Medicare, then each state's own income tax, and then the population-weighted cost of a one-bedroom rental, groceries, home energy and gasoline across 12,694,798 people in 102 counties in Illinois and 4,534,824 people in 120 counties in Kentucky.
Taxes: what each paycheck loses
Federal income tax ($5,072) and FICA ($4,590) on $60,000 are the same on both sides of the border. State income tax takes $2,829 in Illinois and $2,269 in Kentucky, which leaves take-home pay of $47,510 and $48,069.
At $100,000
At $100,000 take-home pay is $74,092 in Illinois and $75,032 in Kentucky, a difference of $940. The gap widens with income because graduated state brackets take a growing share.
Living costs
One-bedroom rent averages $1,489 a month in Illinois and $946 in Kentucky, so Kentucky is $543 a month cheaper for housing. Food costs $3,436 a year in both, because the USDA Thrifty Food Plan is a national figure; home energy $2,110 and $1,874, and gasoline $1,471 and $1,470. Together the basics cost $24,883 a year in Illinois and $18,132 in Kentucky.
What the Census adds
Median household income is $83,390 in Illinois and $63,726 in Kentucky. Homeowners pay a median of $5,298 a year in property tax in Illinois and $1,544 in Kentucky. Commuters travel 27.8 minutes each way on average in Illinois and 24.0 in Kentucky.
Method
Taxes use the 2025 rules for a single filer with wage income only and the standard deduction. Housing and living costs are county figures from HUD (one-bedroom Fair Market Rent), the USDA Thrifty Food Plan and state energy prices from the Energy Information Administration, averaged across each state's counties and weighted by population, so large counties count more. Local income taxes are not included. Counties differ widely inside every state, so use the county pages for a specific place.