As an intellectual center of the community, it sponsors exhibitions, concerts, lectures, and other educational and cultural programs.

[2] The institution's 1805 Federal style building, located on Market Square at the city's heart, was acquired by the society in 1823.

It was designed by architect Bradbury Johnson (1766–1820) as the office for the New Hampshire Fire & Marine Insurance Company, which went bankrupt.

[2] In 1981 and 1995, the Athenæum expanded into the adjacent building at 6–8 Market Square to accommodate its Shaw Research Library and Randall Gallery.

As a consequence, the Athenæum has a strong emphasis on maritime history, particularly shipbuilding at Badger's Island and the Portsmouth Naval Shipyard, both located across the Piscataqua River in Kittery, Maine.