The Whitehouse–Mechanicsville Historic District is a historic district located along old New Jersey Route 28, Mill, Lamington and School Roads in Whitehouse and Mechanicsville, unincorporated communities in Readington Township, Hunterdon County, New Jersey.

It was added to the National Register of Historic Places on March 17, 2015 for its significance in architecture and community development.

[3] The villages of Whitehouse and Mechanicsville developed along the 1806 stage coach route, then known as the New Jersey Turnpike, that went between Easton, Pennsylvania and New Brunswick, New Jersey.

The house at 20 Old Highway 28 was built c. 1860–1870 with Italianate and Greek Revival styles.

The Ryland Inn was built with Gothic Revival style with Italianate influences.