I am looking for data on the total GDP of most or all United States counties. (GDP per capita is fine too, I can multiply it by population). I am not sure if this data exists, but I know there are definitely sub-national statistics on GDP, for example, there is data on GDP of each individual state and for most Metro Areas in the country.
Also, income and GDP are different. This wikipedia article is the closest thing I've been able to find, but it lists counties by their income per capita, not GDP per capita. You can tell, because they have it listed per state as well, and if you multiply the income per capita by population, it doesn't come anywhere close to the state GDP for most states.