Pennsylvania State Route 403 is a north-south highway in North-Central Somerset County. It runs from U.S. Rt. 30, at Stoystown, to the Somerset/Cambria County Line, near Ferndale. PA St Rt 403 passes through the following towns in Somerset County. Stoystown Hooversville Hollsopple Davidsville Tire Hill PA St Rt 403 is not multi-plexed in Somerset County. PA St Rt 403 intersects the following highways in Somerset County. U.S. Rt. 30, at Stoystown.