Pennsylvania Route 666

Pennsylvania Route 666
Route information
Maintained by PennDOT
Length	33.557 mi[1] (54.005 km)
Existed	1928–present
Major junctions
West end	US 62 in Hickory Township
East end	US 6 in Sheffield
Location
Country	United States
State	Pennsylvania
Counties	Forest, Warren
Highway system
Pennsylvania State Route System Interstate US State Scenic Legislative
← PA 664 → PA 669

Pennsylvania Route 666 (PA 666) is an east–west state route located in northwest Pennsylvania. The western terminus of the route is at U.S. Route 62 (US 62) in the Hickory Township municipality of East Hickory, and its eastern terminus is at US 6 in the hamlet of Sheffield. It cuts through most of Allegheny National Forest, and is therefore sparsely populated, with the largest settlement along the road being Endeavor. Its official name is the David Zeisberger Memorial Highway.

The route was assigned in the 1928 numbering of State Routes in Pennsylvania. The highway originally ended in the town of Nebraska until being extended southward along other streets. The route was realigned in 1946 onto its present routing. The highway has remained the same since.