The Betsie River is a 54.0-mile-long (86.9 km) stream in the northwest part of the U.S. state of Michigan.The name is derived from the French la rivière aux Bec-scies, meaning river of sawbill ducks (bec-scie). Other alternate names include Aug-sig-o-sebe, Aux Buscies, Betsey's River, Black Robe, Gay-she-say-ing, Riviere du Pere Marquette, Sawbill Ducks, and Shelldrake Ducks. The river is mostly within Benzie County (which takes its name from a variant pronunciation of the river), although the river rises in southwest Grand Traverse County and flows briefly through northern Manistee County, Michigan.