Ohio Rev. Code § 157.03
The plane co-ordinates of a point on the earth's surface, to be used in expressing the position or location of such point in the appropriate zone of the systems specified in section 157.01 of the Revised Code, shall consist of two distances, expressed in United States survey feet and decimals of a United States survey foot when using the Ohio co-ordinate system of 1927, and expressed in metres and decimals of a metre when using the Ohio co-ordinate system of 1983. One of these distances, known as the "x co-ordinate," shall give the position in an east and west direction; the other, known as the "y co-ordinate," shall give the position in a north and south direction. These co-ordinates shall be made to depend upon and conform to plane rectangular co-ordinate values for the monumented points of the North American horizontal geodetic control network as published by the United States department of commerce and whose plane co-ordinates have been computed on the systems defined in this chapter. Any such station may be used for establishing a survey connection to either Ohio co-ordinate system.
R.C. §157.03