The East Branch Pecatonica River is a tributary of the Pecatonica River, approximately long,[1] in southwest Wisconsin in the United States.
It rises in the hills of eastern Iowa County, approximately 2miles north of Barneveld and approximately west of Madison. It flows south past Barneveld, Blanchardville, and Argyle, and joins the Pecatonica in southeast Lafayette County, approximately 5miles north of the state line with Illinois.