Mountain Top is a census-designated place (CDP) in Luzerne County, Pennsylvania, United States. As of the 2010 census, the CDP population was 10,982.
Mountain Top is located along Pennsylvania Route 309 (south of Wilkes-Barre) in and around the townships of Fairview, Wright, Dorrance, and Rice.
The area's proper name is "Mountain Top." The local historical society uses the spelling "Mountain Top." The United States Postal Service uses the spelling "Mountain Top" for ZIP Code 18707, and the Pennsylvania Department of Transportation spells it "Mountain Top" on a Pennsylvania driver's license. However, some businesses in Mountain Top spell their community as a single word, "Mountaintop."
Mountain Top, once named Penobscot, PA, is located at 41°8′7″N 75°54′16″W (41.1353022, -75.9044749) in the shadow of Mount Penobscot (or Penobscot Knob). According to the United States Census Bureau, the CDP has a total area of 15.1 square miles (39.0 km2), all of it land.
Mountain Top is located in the saddle pass atop the drainage divide between the Susquehanna River basin (to the north and west) and the Lehigh River basin (to the east and south), so sits astride an important land communications corridor bridging the two watersheds below. It is just 8 miles (13 km) northwest of White Haven, at the head end of the Lehigh River, and in the heights above Hazleton, only 10 miles (16 km) south of Wilkes-Barre on Pennsylvania Route 309. Consequently, even though regional railroads are much diminished in scope and influence, Mountain Top yard, once used as a marshaling yard at the top of the Ashley Planes funicular (cable driven) railway, is still an important regional element of the transportation infrastructure connecting Allentown and Philadelphia with points north and west via trackage to several yards in New York State.
Mountain Top is elevated at 1,558 feet (475 m) above sea level.
As of the census of 2000, there were 15,269 people, 5,556 households, and 4,394 families residing in the CDP. The population density was 224.0 people per square mile (86.5/km2). There were 5,774 housing units at an average density of 84.7/sq mi (32.7/km2).