Wow, check out this amazing view. We dug up this gem on the Library of Congress site. The full caption is below.
West-southwest view with Maryland Ave. SW and B Street SW (i.e., Independence Ave. SW) to the left, Maine Ave., 3rd, 4 1/2, and 6th streets SW to the center; view includes The Mall, Washington Armory, Armory Square Hospital, Smithsonian Castle, Washington Canal, Botanic Garden, Gas Works, Washington Monument, under construction, and the Potomac River.
There is so little to be found of southwest DC — “the Island” — and I was very glad to see this. It looks like Maryland Avenue was in the process of becoming a rail bed.
I believe the brick building smack in the center of the photo is the famous bawdy house of Mary Hall. You can find out more here: http://monumentalwashington.zenfolio.com/blog/2015/8/famous-hookers