The Family History Library has maps dating from the Revolutionary War era and the earliest land subdivisions to present-day county highway maps. These include historical atlases, mostly published in the 1870s, from 60 counties.
Several guides to the history of Ohio's counties and boundary changes have also been published. They include:
Long, John H., ed. Historical Atlas and Chronology of County Boundaries, 1788-1980. Scale: 1:633,600. Illinois, Indiana, Ohio. Boston, Massachusetts: G.K. Hall, 1984. (FHL 973 E7hL v. 2; fiche 6051427 [set of 6].) It offers an excellent collection of state maps, showing when and where each county changed boundaries.
Phillips, Louis W. Jurisdictional Histories for Ohio’s Eighty-Eight Counties, 1788-1985. Bowie, Maryland: Heritage Books, c.1986. (FHL book 977.1 E3p.) It is a valuable guide to Ohio's counties in jurisdictional histories.
The following books may also aid your research:
Brown, Lloyd Arnold. Early Maps of the Ohio Valley. Pittsburgh, Pennsylvania: University of Pittsburgh Press, 1959. (FHL book 973 E3b.) This covers the era 1673 to 1783.
Walling, H.F. Atlas of the State of Ohio from Surveys. 1868. Reprint, Knightstown, Indiana: Bookmark, 1976. (FHL book Q 977.1 E7w; film 982071 item 9.) This includes city ward maps.
The Family History Library has:
Ward Maps of United States Cities. Washington, D.C. : Library of Congress, [1975?]. (FHL film 1377700; FHL fiche 6016620-6016629 for Cincinnati, 1831-1896; FHL fiche 6016630-6016636 for Cleveland, 1852-1899; FHL fiche 6016637-6016641 for Columbus, 1856-1894.)
Landowner maps are especially valuable. These maps show the lands of a county, with the names of the owners written on them. Most of these maps date between 1860 to 1900. A checklist of 19th-century United States county maps in the Library of Congress is:
Stephenson, Richard W., comp. Land Ownership Maps. Washington, D.C.: Library of Congress, 1967. (FHL book 973 A3Loc; FHL fiche 6048262.) This checklist records 1,449 United States county land ownership maps, 69 of which are Ohio counties.
Maps are listed in the Place Search of the Family History Library Catalog under:
OHIO - MAPS
OHIO, [COUNTY] - MAPS
OHIO, [COUNTY], [CITY] - MAPS