Built 1848–1850, they are among New Hampshire's best examples of Greek Revival architecture, having undergone only relatively modest alterations.

The front facade of each house has a projecting gable supported by three two-story fluted Doric columns, with a porch accessible from the second floor.

The Foster house has had an addition built in the corner between the main block and the ell, which includes a projecting bay window on the front facade.

The Cleaves House has had a larger number of owners, including former Governor of New Hampshire Matthew Harvey and Mary Baker Eddy, founder of the First Church of Christ, Scientist.

[3] In 1985, the Longs gifted the house to Longyear Museum, dedicated to Eddy's life history, which restored it to the period of her occupancy, 1889–1892.