Circus Historical Society
This site is a comprehensive resource for circus information. It includes publications, helpful links, photographs, ads and logos, and online circus history. It also covers specific circus topics like early side show, setting up the tent, and early circus seating, to name a few. The "logos" link allows you to see if a 20th century circus had its origins where you live. There are three from Pennsylvania listed: Hoxie Bros. And Great American Combined Circus, Harrisburg, Pennsylvania, 1983; Wheeler Bros. Greater Shows, Oxford, Pennsylvania, 1914-1915; and Reo Bros. Circus, Upper Darby, Pennsylvania, 1941.
Referenced in:
"The Greatest Show on Earth: Then and Now"