Johnsonburg is a borough in Elk County, Pennsylvania, 124 miles (200 km) northeast of Pittsburgh and 115 miles (185 km) south of Buffalo, New York, in a productive farming and lumbering region. Paper mills were once common here, and Domtar still maintains a paper mill there today. In 1910, 4,334 people lived here. The population was 3,003 at the 2000 census.
It was founded in 1810 and incorporated in 1891.
Johnsonburg is located at 41°29′38″N 78°40′47″W (41.493950, -78.679600).
According to the United States Census Bureau, the borough has a total area of 3.0 square miles (7.8 km2), all of it land.