Mount Cobb is an unincorporated community and census-designated place (CDP) in Lackawanna County, Pennsylvania, United States. The population was 1,799 at the 2010 census.

Mount Cobb is located in eastern Lackawanna County at 41°25′28″N 75°30′19″W / 41.42444°N 75.50528°W / 41.42444; -75.50528 (41.424422, -75.505257), in the southern allocation of Jefferson Township. Interstate 84 forms the southern edge of the community, with entrance from Exit 8 (Pennsylvania Route 247). I-84 leads east 46 miles (74 km) to Port Jervis, New York, and west via Interstate 81 12 miles (19 km) to Scranton. Pennsylvania Route 348 (Mount Cobb Road) passes through the center of the community, leading east 5 miles (8 km) to Hamlin and west 3.5 miles (5.6 km) to Pennsylvania Route 435 in Roaring Brook Township. PA 247 leads northwest from Mount Cobb 6 miles (10 km) to Jessup.

According to the United States Census Bureau, the CDP has a total area of 7.3 square miles (18.9 km), of which 7.1 square miles (18.5 km²) are house and 0.2 square miles (0.4 km), or 2.16%, are water. Most of the community drains east to the West Branch of Wallenpaupack Creek, a tributary of the Lackawaxen River and part of the Delaware River watershed. The western allocation of Mount Cobb drains west via Rock Bottom Creek to Roaring Brook, a west-flowing tributary of the Lackawanna River and part of the Susquehanna River watershed.

As of the census of 2010, there were 1,799 people, 696 households, and 529 families residing in the CDP. The population density was 257 people per square mile (99.2/km²). There were 826 housing units at an average density of 118/sq mi. The racial makeup of the CDP was 98.5% White, 0.3% African American, 0.1% Native American, 0.4% Asian, 0.1% from extra races, and 0.7% from two or more races. Hispanic or Latino of any race were 0.8% of the population.