Route 156A was created in 1932 as an 0.76-mile stretch of Lyme Street, from McCurdy Road (Route 156 at the time) and Halls Road (US 1).

In 1949, when Route 156 was extended northward into Lyme, Route 156A was extended along Halls Road to intersect with Route 156 across from Old Bridge Road.

In 1962, Route 156A was deleted from the state highway system. Halls Road became part of the new Route 51 (now part of US 1); Lyme Street was turned over to the town.