This picturesque, cobblestone lane has been occupied since the 1720s, making it America's oldest residential street. The 32 well-preserved Federal and Georgian row houses are inhabited by regular Philadelphians, so be considerate in the narrow space.
The street is named after Jeremiah Elfreth, an 18th-century blacksmith and property owner. One of the brick houses is periodically open as a museum; if you come 1pm on Friday and 1pm or 3pm on Saturday or Sunday, you can join a tour of both the house and the alley.