It flows southeast for several hundred feet, alongside Cully Run Road.

Several hundred feet further downstream, it reaches its confluence with Fishing Creek, not far from the community of Maple Grove.

[1] Culley Run joins Fishing Creek 21.16 miles (34.05 km) upstream of its mouth.

[4] The Pennsylvania Department of Transportation also has a permit to maintain a box culvert made of reinforced concrete on the stream.

[3] Culley Run was entered into the Geographic Names Information System on August 2, 1979.

[3] In 2004, the Columbia County Natural Areas Inventory recommended protecting Culley Run.

[3][9] Brasch states that the stream is most likely named after Alexander Colley, Sr., a surveyor and teacher who served on the Pennsylvania legislature from 1822 to 1823.