In 1846, Alfred Kelley, Representative from Cuyahoga County, introduced legislation into the Ohio General Assembly that provided for taxation by a uniform rule.  All property, real and personal, were taxed at their true value, except what might be expressly exempted.  The act required county auditors to provide to the district tax assessors information containing a description of each tract and lot of real property within the assessors’ district with the owners’ name and the number of acres that they owned.  It also obligated the auditor to deliver to each assessor “a map of each township and town within such district, with such plat books as may be necessary to enable the district assessor to make a correct plat of each section, survey and tract, in his district.”  This section of the tax code remained in revisions to the taxation system in 1853 and 1859 when new property appraisements were authorized. Legislation in 1868 directed that beginning in 1870 maps were to be made “and every tenth year thereafter”.  In 1913, the power of overseeing the creation of tax maps was shifted from the county auditor to the county commissioners.  The legislature authorized the making of tax maps only when “in the opinion of the county commissioners” it was necessary for “the proper appraisal of real estate”.

This system was maintained when the current Ohio Revised Code (O.R.C.) was created in 1952.  Currently, the legislation is encompassed in O.R.C. 5713.09 entitled Tax Maps of Subdivisions .  It was last updated in 1969 and reads as follows:

The board of county commissioners may designate the county engineer to provide for making, correcting, and keeping up to date a complete set of tax maps of the county, and shall employ the necessary number of assistants. Such maps shall show all original lots and parcels of land, and all divisions, subdivisions, and allotments thereof, with the name of the owner of each original lot or parcel and of each division, subdivision, or lot, all new divisions, subdivisions, or allotments made in the county, all transfers of property, showing the lot or parcel of land transferred, the name of the grantee, and the date of the transfer so that such maps shall furnish the county auditor, for entering on the tax duplicate, a correct and proper description of each lot or parcel of land offered for transfer. Such maps shall be for the use of the county board of revision and the auditor, and shall be kept in the office of the auditor.

With the advent of Geographic Information Systems (GIS) mapping technology in the 1990s, tax maps drafted by the county engineer became obsolete.  The county auditor, once again, oversees and coordinates the mapping system in conjunction with the county engineer.  Orthophotos are shot and overlaid on a master map of the county.  These electronic maps depict buildings, land characteristics and uses, property lines, soil types, hydrography, along with containing property owners as well as political boundaries.

Please note that the plat (tax) maps are divided into two categories - Township Plat (Tax) Maps and Village Plat (Tax) Maps.