It features a central three-bay entry pavilion that projects slightly from the facade; there are pilaster elements flanking and between the windows of this section.

Inside, the lobby area is richly colored, with multiple shades of marble used on the floors and decorative wall and ceiling elements.

It also retains a number of original features, such as writing desks and light fixtures.

[1] In late 2018, the building was renamed by an Act of Congress in honor of Thomas P. Costin Jr.,[3] the 45th and youngest Mayor of Lynn, who later served as Postmaster for the Lynn District from 1961 to 1992.

This article about a National Register of Historic Places listing in Essex County, Massachusetts, is a stub.