The North Branch flows 61.4 miles (98.8 km)[1] from a point 8 miles (13 km) east of Lancaster, Minnesota to its confluence with the South Branch.

The South Branch rises in Roseau County, approximately 5 miles (8 km) southeast of Badger, and flows 99.4 miles (160.0 km) west to the North Branch.

[1] It passes the town of Greenbush before entering Kittson County and passing the town of Lake Bronson.

At Hallock, the Middle Branch enters from the east.

The 28.0-mile (45.1 km) section of the South Branch downstream from the Middle Branch is shown on federal topographic maps as the main stem of Two Rivers.