State Route 170 (SR 170) is a north–south running
state route located in
Mahoning and
Columbiana counties in northeast
Ohio. It runs within a few miles of the
Pennsylvania border for much of its route as it passes through the eastern parts of the two counties. The southern terminus is at an interchange with
U.S. 30,
State Route 7, and
State Route 11 near
Calcutta, and the northern at
U.S. 62 in
Youngstown.
ODOT extended the northern terminus from the previous point of
Interstate 680, changing signs on July 16 and 17, 2008.[2]
History
In 1924, it became the original state highway where it routed from East Palestine to Petersburg. In 1931 the highway extended to East Liverpool along a previously unnumbered road. Later in 1962 it was extended to 1-mile (1.6 km) north of North Kingsville along previous route 90. The road was truncated at 3 miles (4.8 km) north of Poland in 1970.[3] In 2008, it extended 3 miles (4.8 km) to U.S. 62 in Youngstown along the former
Route 625.[2][4]