There were two survivors, the driver of the SUV and one of her children, the Pittsburgh Post-Gazette reported.'
The crash occurred about 4:30 p.m. EDT Saturday on State Route 219 in the Allegheny National Forest, the Post-Gazette said.
The Kane Republican reported authorities had yet to determine why the southbound SUV's driver, Kathy Douglas, 36, of Kane, crossed the highway's center line, smashing into a northbound car carrying four people who all died.
The victims in the car were identified as Gary Beimel, 62, Elaine Beimel, 55, David Cuneo, 54, and Florence Donachy, 81, all of St. Mary's.
Douglas' 12-year-old daughter Olivia Douglas and 6-year-old nephew, Jarrett Costanzo, died at the scene, the Post-Gazette said.
Police said Douglas and her 10-year-old son, whose name wasn't available, were flown to a hospital for treatment of serious injuries, the Post-Gazette said.