The round pigtoe was historically found in the upper Mississippi drainages and the St. Lawrence drainage. Generally it is found from western New York and Ontario west through Wisconsin and Minnesota to the southeastern portion of South Dakota, south to Oklahoma, Arkansas, Mississippi and Alabama. Its eastern range includes western Virginia, West Virginia, and western Pennsylvania.
In Michigan P. sintoxia is found in mid-Michigan drainages, mainly from the Muskegon and Saginaw River systems on through the southern river systems. Specimens have also been collected in the Sturgeon River in the upper peninsula.
Biogeographic Regions: nearctic (Native )
- Burch, J. 1975. Freshwater unionacean clams (Mollusca: Pelecypoda) of North America. Hamburg, Michigan: Malacological Publications.
- COSEWIC, 2004. COSEWIC assessment and status report on the round pigtoe, Pleurobema sintoxia, in Canada. Committee on the Status of Endangered Wildlife in Canada, 2004: 1-33. Accessed September 12, 2006 at http://www.sararegistry.gc.ca/virtual_sara/files/cosewic/sr_round_pigtoe_e.pdf.
- Cummings, K., C. Mayer. 1992. Field guide to freshwater mussels of the Midwest. Champaign, Illinois: Illinois Natural History Survey Manual 5. Accessed August 25, 2005 at http://www.inhs.uiuc.edu/cbd/collections/mollusk/fieldguide.html.