South Penn Run is a 1.24 mi (2.00 km) long first-order tributary to West Branch Tunungwant Creek.

[2] This is the only stream of this name in the United States.

[1] South Penn Run rises about 4 miles (6.4 km) northwest of Lewis Run, Pennsylvania, and then flows east-southeast to meet West Branch Tunungwant Creek about 3 miles (4.8 km) northwest of Lewis Run, Pennsylvania.

South Penn Run drains 0.69 square miles (1.8 km2) of area, receives about 47.1 in/year (120 cm/year) of precipitation, and is about 69.41% forested.

[3]