Monterey Square was laid out in 1847 on Bull Street, in the southernmost row of squares just north of Forsyth Park. It commemorates the 1846 capture of Monterrey by U.S. forces under Zachary Taylor during the Mexican-American War, though the square's name uses the single-r spelling. At its center is the 1853 monument to General Casimir Pulaski, the Polish cavalry officer mortally wounded in the 1779 Siege of Savannah. Remains of an unknown Revolutionary soldier, believed by some to be Pulaski himself, are said to lie beneath it.

All but one of the buildings around the square are original to it. They include Congregation Mickve Israel's 1878 synagogue, one of the few Gothic-style synagogues in America. On the west side is the Mercer House, designed by John S. Norris for General Hugh W. Mercer. Construction began in 1860 and was interrupted by the Civil War, and the house was finished around 1868 for a later owner. No Mercer ever lived there. It was home to the Alee Shriners for a time, and in 1969 the antiques dealer and preservationist Jim Williams bought and restored it. The house and the square are central to John Berendt's 1994 book Midnight in the Garden of Good and Evil and the 1997 film.

The square is public and open at all hours. The Mercer-Williams House is a separate museum with its own daytime tours, and its upper floors are private.