The median income of Mercer County residents was an inflation-adjusted $24,100 per year. Mercer County had 45,805 households in 2017, with a population of 113,623.
The county with the highest median resident income in the state was Chester County. Chester County's median income was $40,145 per year after adjusting for inflation – $16,045 more than Mercer County. It had 188,613 households in 2017 and a population of 514,652.
Forest County had the lowest annual resident income among counties in Pennsylvania, with a median income of only $15,451 per year. That was $8,649 less than the median income in Mercer County at the time. Forest County had 1,473 households in 2017 and a population of 7,388.
The table below shows the state's counties ranked by median annual resident earnings in 2017.