[1][2] It flows west-northwest for more than a mile, crossing Pennsylvania Route 42, reaching the base of the mountain, and entering a valley.

The stream then turns south-southwest for several tenths of a mile before passing through two wetlands and three ponds and entering Beaver Lake.

The stream's valley then widens and it turns southwest for several tenths of a mile before reaching its confluence with Little Muncy Creek.

[1] Wisconsinan Outwash, which consists of stratified sand and gravel, forms terraces along the flank of the valley of Beaver Run.

The stream's valley, which runs north-to-south (parallel to the glaciers during the Ice Age), has been significantly deepened by glacial scour.

[4] This variant name appears in the 1880 book The Geology of Lycoming County by Andrew Sherwood and Franklin Platt.

A concrete frame bridge carrying T-706 over the stream was built in the same year 1.7 miles (2.7 km) south of Beaver Lake and is 27.9 feet (8.5 m) long.

A steel stringer/multi-beam or girder bridge carrying State Route 2061 6 miles (9.7 km) north of Lairdsville was constructed over the stream in 1939 and repaired in 1990.

A prestressed box beam or girders bridge carrying State Route 2077 over Beaver Run was built in 1985 1 mile (1.6 km) north of Lairdsville and is 48.9 feet (14.9 m) long.