It is approximately 2.3 miles (3.7 km) long and flows through Dennison Township.

[2] The elevation near the mouth of Reilly Creek is 1,158 feet (353 m) above sea level.

[2] Reilly Creek was entered into the Geographic Names Information System on August 2, 1979.

Its identifier in the Geographic Names Information System is 1184879 and it is described as a "2 mile long tributary of Nescopeck Creek".

[4] The Pennsylvania Fish and Boat Commission has a water quality sampling station on Reilly Creek.

[2] Reilly Creek is considered by the Pennsylvania Department of Environmental Protection to be a Coldwater Fishery.