Alps' Roads: Various locations in the U.S. and Canada.
Greg's Road Sign Pages: Wide coverage in the United States and Canada.
Gribblenation.com: Extensive information primarily covering the eastern third of the continent.
Neil's Summer 2002 Roadtrip: Photo log of the Upper Midwest and Ontario, Canada.
Piehl Canada Trip: U.S. and Canada coverage from a 2002 road trip.
Roadfan.com: The Lincoln Highway, the National Road, eastern Canada, and the Lower Mississippi River, Great Lakes, and New England areas in the United States.
Roamer1's Road Pages: Covers mostly the Southeast U.S. but also covers various other areas in the U.S. and Canada.
State Line Signs: Includes personally-taken examples from both U.S. states and Canadian provinces.
State Route Salute: State and province route marker gallery.
The Chris Kadlec Road Photos Gallery: Various views from trips around the continent.
Why Do You Have So Many Pictures of Road Signs?: Extensive U.S. and Canada coverage.