Ind. Code § 32-19-1-1

Sec. 1. The systems of plane coordinates that have been established by the National Ocean Survey/National Geodetic Survey (formerly the United States Coast and Geodetic Survey) or its successors for defining and stating the positions or locations of points on the surface of the earth within Indiana are known and designated as the "Indiana coordinate system of 1927" and the "Indiana coordinate system of 1983".