The Middlebury River is a tributary river of Otter Creek in Addison County, Vermont. Three branches feed the river from origins in Green Mountain National Forest. The river is 18.6 miles (29.9 km) long, has a watershed of 62.8 square miles (163 km2), and is located southeast of Lake Champlain. The river passes through Ripton, Middlebury and Salisbury.