The highway has its southern terminus at a T-intersection with SR 56 in the unincorporated community of South Bloomingville.

The northern terminus of SR 664 is also at a T-intersection, this time with SR 256 on the Fairfield–Perry county line approximately 4.75 miles (7.64 km) north of the village of Rushville.

Along its way, SR 664 passes through portions of Hocking and Fairfield Counties.

No segment of this highway is included as a part of the National Highway System, a network of routes identified as being most important for the country's economy, mobility and defense.

[9] The realignment was needed to reduce the conflict between traffic on the road and pedestrians in the vicinity of the park.