Its original main portion is a U-shaped granite structure, the U open to Congress Street.

The central portion is three stories in height, with roof dormers fronted by a low balustrade.

There are three entrances, accessed via a broad set of stairs; the central one is topped by the city seal.

Inspired by New York City Hall, John M. Carrère considered it one of his finest works.

[7] Brass plaques, mounted on the pillars at the base of the steps to the building, commemorate soldiers who fought in the Spanish-American War through Vietnam.