It features a high level of ornamentation, possibly due to the influence of James Farley, a native of the Haverstraw area who was Postmaster General at that time.

[1] Its square main block is a one-story, five-bay structure of brick in Flemish bond with an east wing and a slightly projecting pavilion on the north (front) elevation.

[1] Granite steps and a wheelchair ramp lead up to the main entrance, modern aluminum doors between two Doric pilasters supporting an entablature with swan's-neck pediment.

[1] In 1931 the construction of a new post office in Haverstraw was authorized when Congress passed an amended version of the Public Buildings Act of 1926, in an early attempt to ease the Great Depression.

Construction did not begin until 1935, when James Farley, then Postmaster General, a native of nearby Stony Point, laid the cornerstone.

Haverstraw's, designed by Treasury Department Supervising Architect Louis Simon, shares a similar basic form with the Norwich post office upstate, built two years earlier.