Mount Carmel is a borough in Northumberland County, Pennsylvania, United States, located in the Coal Region of the central Susquehanna River Valley. The population was 5,725 at the 2020 census. Situated 88 miles (142 km) northwest of Philadelphia and 71 miles (114 km) northeast of Harrisburg, the borough is completely encircled by Mount Carmel Township and sits within the Western Middle Anthracite Field. Mount Carmel is known for its role in the anthracite coal industry, for being home to Lieutenant General James M. Gavin of World War II fame, and for being the site of what the Smithsonian Institution identifies as the world's first isolated electrical generating plant, established in 1883.