It was designed by J. Maximilian M. Godefroy, a French émigré who also designed the St. Mary's Seminary Chapel on North Paca Street on the northwest edge of the City and the Battle Monument in the former Courthouse Square on North Calvert Street between East Lexington and Fayette Streets commemorating the Battle of Baltimore of September 1814 at North Point and the bombardment of Fort McHenry in the War of 1812, and assisted the famed British-American architect Benjamin Henry Latrobe in designing the Merchants' Exchange Building at South Gay Street, between Second (now Water) and East Lombard Streets, the then-largest building n America, an H-shaped, low domed on a drum Greco-Roman structure with a large rotunda beneath and a second-story interior catwalk balcony around the atrium.

In the rear, on the north side along the West Hamilton Street alley is the Enoch Pratt Parish Hall, also housing church offices, constructed in 1879 of bricks salvaged from the townhouses torn down at West Mulberry at Cathedral Street for the first Central Building of parishioner Enoch Pratt's gift to the City of Baltimore, of a central library and four regional branches in 1882, constructed and opened 1886 (current building replaced it in 1931-33).

The Parish Hall was renamed to commemorate his influence and guidance in the early years in 2008 and its interior is being restored to its Victorian appearance.

One block north of Benjamin Latrobe's Baltimore Cathedral, (now the Basilica of the Assumption of Mary and the first cathedral constructed for Roman Catholics in America), The First Unitarian Church is located in the Mount Vernon-Belvedere neighborhood north of downtown and was formerly part of "Howard's Woods" on the estate north of old Baltimore Town of Col. John Eager Howard, commander of the "Maryland Line" regiment of the Continental Army in the American Revolution where the Washington Monument and its four square parks were laid out in 1821, two blocks north.

[7] It is included in the "Cathedral Hill Historic District" and the newly designated "Baltimore National Heritage Area".