Local data (i.e. state-level or county-level) can be found from the national source, in this case the BEA, or from a local demographer’s office.
Local Source
County Level Income Data for Minnesota, 2005
The state demographer’s office of Minnesota prepares and publishes reports and data subsets like this one for the state of Minnesota. When you’re looking for state specific data like this, it is a good idea to look for the state’s demographer web site.
“Personal income is an estimate of income received by residents of a state. These income estimates are part of the National Income and Product Accounts prepared by the Bureau of Economic Analysis and are derived from a wide range of administrative records.
Personal income consists of three components: earned income, asset income and transfer payments. Earned income includes wages and salaries, proprietors’ income, farm income, and other labor income, which is primarily employers’ contributions to private benefit plans. Asset income is received from interest payments, dividend payments and rent. Transfer payments are, for the most part, government payments to individuals, such as Social Security, medical, income maintenance, unemployment insurance and veterans’ benefits. The data included here is presented on a per capita basis using population estimates provided by the U.S. Bureau of Economic Analysis.” (from web site)
National Source
More (for other states and for longer periods of time) state and local personal income data can be downloaded from the web site of the BEA (Bureau of Economic Analysis).