Built in 1866, it is one of the town's prominent former public buildings, and an important surviving school commission of architect George M. Harding.

The former Union School building stands just outside the main downtown area of Searsport, on the east side of Mt.

It is oriented facing south, with a five-bay facade that has a central entrance sheltered by a porch supported by narrow turned columns.

Sash windows are set in rectangular openings, with stone sills and lintels, and there is a mansarded gable at the center of the roof above the entrance.

The side elevations have fully pedimented and bracketed gables, with round-arch Italianate windows at their centers.