The House, a site on the Black Heritage Trail, is a private residence and is not open to the public.
Wikipedia https://en.wikipedia.org/wiki/George_Middleton_(activist)
More information http://www.nps.gov/boaf/historyculture/george-middleton-house.htm
Address 5 Pinckney Street, Boston, MA 02114, USA
Coordinates 42°21'32" N -71°3'55.001" E