Mifflinburg's finest mid-nineteenth house was built on Market Square by merchant Henry Gast. The rectangular block has a facade laid in hard pink brick from Philadelphia, a white marble foundation and sills, and double gable-end chimneys. The attic windows in the frieze and the transom-light entrance are original Greek Revival features; the pedimented portico and side porch are later additions. The Mifflinburg jail (c. 1885) in the backyard has vertical siding typical of regional outbuildings.