The median income of Douglas County residents was an inflation-adjusted $28,500 per year. Douglas County had 7,580 households in 2017, with a population of 19,830.
The county with the highest median resident income in the state was DuPage County. DuPage County's median income was $38,289 per year after adjusting for inflation – $9,789 more than Douglas County. It had 340,669 households in 2017 and a population of 931,826.
McDonough County had the lowest annual resident income among counties in Illinois, with a median income of only $20,344 per year. That was $8,156 less than the median income in Douglas County at the time. McDonough County had 11,481 households in 2017 and a population of 31,597.
The table below shows the top 100 counties ranked by median annual resident earnings in 2017.