SIDNEY, a city and the county-seat of Shelby county, Ohio, U.S.A., on the Miami river, about 33 m. S. by W. of Lima. Pop. (1890) 4850; (1900) 5688, including 282 foreign-born and 108 negroes; (1910) 6607. Sidney is served by the Cleveland, Cincinnati, Chicago & St Louis, the Cincinnati, Hamilton & Dayton, and the Western Ohio (electric) railways. The city is situated on an elevated tableland, in an agricultural region. Sidney has a public library, and a monumental building, a memorial, erected in 1875, to the soldiers in the American Civil War, and now devoted to various public uses. The river here provides some water-power, and the city has various manufactures. Sidney was laid out as the county-seat in 1819, was incorporated as a village in 1831 and first chartered as a city in 1897.