This small Georgian Revival post office has Doric columns and a golden eagle entablature around the entrance. The single story of rough-faced Manitou green sandstone sits under a side-gable roof of flat red tile with a dentiled cornice and a wooden cupola centered on the apex. Original brass lamps and railings flank the marble steps leading to the central entry, and the shiplap-sided gable ends have fan windows. Archibald Musick, a student of Thomas Hart Benton, painted the interior mural, The Legend of Bubbling Springs. The lobby floor is patterned in 24-inch diamonds in dark and light terrazzo, and the walls have 7-foot-high marble wain-scoting.
The post office occupies the former site of Jerome Wheeler's manor house, Windemere. Several of the estate buildings remain, including the bowling alley (1891) at 36 Park Avenue, and the livery barn, converted to apartments, at 42 Park Avenue. The Wheeler Spring, drilled by Wheeler's son-in-law in 1920 and later donated to the city, bubbles from a retaining wall of Manitou sandstone next to the post office.