 It was attached for administrative purposes to Washtenaw County until 1838 when county government was established for Ingham.The county was named for Samuel D. Ingham, the U.S. Secretary of the Treasury under President Andrew Jackson, making Ingham one of Michigan's so-called Cabinet counties.According to the U.S. Census Bureau, the county has a total area of , of which is land and (0.8%) is water.