Glencairn is a castle-like mansion in Bryn Athyn, Pennsylvania, that was home to the Pitcairn family for more than 40 years.

Multi-millionaire businessman Raymond Pitcairn (1885–1966) and his wife, Mildred Glenn (died 1979) built "Glencairn" between 1928 and 1939.

Pitcairn, a member of the New Church himself, had no formal training in architecture and designed the Romanesque-style building using a series of models.

The building also contains elaborate interior mosaics, monel metalwork, Early Medieval stained glass windows, and a replica of the Biblical tabernacle.

Adjacent to "Glencairn" is Raymond Pitcairn's first architectural success, the Gothic Revival Bryn Athyn Cathedral (1913–19), and his father's house "Cairnwood".