The Caldwell one-room schoolhouse, just north of Mercer, Pa., closed …

Photo by Robert K. Yosay | published: May 14, 2012

The Caldwell one-room schoolhouse, just north of Mercer, Pa., closed in 1960 but was reopened in 1962 by the Mercer County Historical Society as a museum. It was the last one-room schoolhouse in the county.