A small but architecturally interesting building one block south of Plaza Colón, the Logia Adelphia was built in the late nineteenth century as the meeting hall of a Mayagüez Masonic lodge. The two-storey façade combines neoclassical detailing with Caribbean iron balconies, and the corner location gives it more presence than its size suggests.
The lodge is still active, so the interior is private, but the building is on the National Register of Historic Places and is one of the better-preserved pieces of pre-earthquake Mayagüez architecture.