The U.S. Post Office–Lancaster Main is a historic post office at 120 Main Street in Lancaster, New Hampshire. The single story brick building was built in 1935, and occupies a visually commanding location in the town center. The brick is laid in common bond, atop a granite base layer and water table. The center of the main facade projects from the main block, and features six pilasters of fluted granite construction topped by a raised parapet. The building's symmetry is upset by the addition of a handicapped access ramp. The building's styling is described as "Starved Classicism", a variant of Art Deco styling that is unusual and rare in the region.