Port Mercer was a small town along the Delaware and Raritan Canal in central New Jersey. Since the canal closed down in 1932, commerce has shifted east to U.S. Route 1, where shopping malls, car dealers, and restaurants are now located. On the west side of the canal, there are still extensive swampy wetlands between Lawrence Township and Princeton.
Glencairn was built by Raymond Pitcairn, “self-taught cathedral architect” (as his New York Times obituary described him) and heir to the massive empire created by his father, John, the founder of PPG industries.
After completing construction of the Bryn Athyn Cathedral of the The New Church, Pitcairn turned to building himself a new house. Located north of Philadelphia (the Philly skyline can be seen from the top of the mansion’s seven-story tower), it was designed by Pitcairn and constructed between 1928 and 1939, while Pitcairn was simultaneously fighting against Roosevelt’s New Deal. Glencairn is built in the Romanesque style out of hand-cut stone and concrete. It contains 90 rooms, including 17 bedrooms, a chapel, and the expansive living room, decorated with both actual Medieval-era items and modern recreations built by artisans in the same style.
See the Curbed article on Virginia Savage McAlester, the author of A Field Guide to American Houses. A revised version of the encyclopedic classic came out a few years ago, and McAlester is now planning a field guide to commercial buildings.