Fosters (sometimes given as Foster) is an unincorporated community in southern Warren County, Ohio, United States. It straddles the Little Miami River in Deerfield and Hamilton Townships. It is located about two miles southwest of Hopkinsville, two miles west of Maineville, and two miles northeast of Twenty Mile Stand just off U.S. Route 22/State Route 3, the 3C Highway. (In the 1930s, the State of Ohio erected a new high bridge over the river that bypassed the community.) The community is in the Kings Local School District and is served by the Maineville post office. The settlement was originally called Foster's Crossing, and had its own post office. It is in the Little Miami telephone exchange.