Wikipedia tells us:
The Betsy Ross House is generally recognized as the place where Betsy Ross lived when she may have made the first American Flag. The house is located just blocks from Independence Hall and the Liberty Bell.
The front part of the building was built around 1740, in the Georgian style, with the stair hall and the rear section added 10 to 20 years later. Ross is believed to have lived here, with her first husband, John Ross (d. 1776), from 1773 to about 1785.
