 PA 10 runs north-northwest through farmland with some homes, crossing the West Branch Brandywine Creek before heading northeast and ascending a small forested hill named Welsh Mountain.PA 10 enters Caernarvon Township in Lancaster County and descends the hill into farmland, continuing to the north and crossing the Conestoga River.The route reaches an intersection with PA 23, at which point it turns northeast for a concurrency along Main Street, a three-lane road with a center left-turn lane, into commercial areas.