State Road 55 runs from the Crawfordsville area in the south to Gary in the north, a distance of approximately 110 miles (180 km).

Northwest of Attica SR 55 leaves US 41 and heads north Oxford.

In Fowler SR 55 leaves US 52 heading north towards Goodland.

In 1930, SR 55 and State Road 53 swapped routes in Lake County.

[4] At some point, the southern terminus of SR 55 was at the intersection with U.S. Route 136, approximately two miles west of Crawfordsville.