Browse Items (1 total) Spatial Coverage is exactly "512 Keystone Ave., Darby (Pa.)" Browse All Search Items Browse Map Browse by Headings Sort by: TitleCreatorDateDate Added Items open in a separate tab. Close the tab to return to this list. 554. Row, old. 600 block Keystone St., Colwyn Address: 512 Keystone Ave., Darby (Pa.) Date: 1955-08 Address is approximate. Most of this row of small houses still stands.