"Once an open space, this area was within the original Spanish presidio. The plaza was probably named in the Mexican years (1821-1854), when soldiers drilled here. Saddle horses for the troops were stabled along the north side, next to the presidio wall. Houses were built over the site beginning in the 1860's."
Downtown Tucson is built over, by, near the original Mexican presidio (fort) built by the Santa Cruz River, which ran year around back then. Bits and pieces keep showing up but since the original buildings were mainly adobe there isn't much left.
The Plaza Militar is at the entrance of the Tucson Museum of Art, across the street from the old Pima Courthouse and on the edge of a few blocks of wonderful historic homes.
(
visit link)