Its eastern terminus was at a T-intersection with SR 121, adjacent to Darke County Airport about 1.5 miles (2.4 km) southwest of Versailles.

Created in the middle of the 1920s, SR 242 ran through very flat farm country in the northeastern portion of Darke County.

The vast majority of the state highway passed through farmland, with the occasional home appearing along the way.

Running due east along the north side of the county airport, the route entered Wayne Township prior to arriving at its endpoint at its junction with SR 121, where the intersecting state highway forms the southern and eastern legs of the T-intersection.

[9] Earlier proposals for the route included ODOT taking over the entire length of Chase Road (which runs along the southern edge of the airport) to SR 121.