Next, the route meets PA Route 221, and the two overlap for just over a mile, heading northwest through the village of Prosperity. After the village, Route 18 leaves the concurrency and heads northward through the villages of Van Buren, Lagonda, and Gabby Heights as it approaches the city of Washington nearly  later. In Washington, Route 18 briefly overlaps with US 40, and the routes head west, intersect with the western terminus of PA Route 136, and then turn northwest.
Next, the route intersects PA Route 221, and they overlap for just over a mile, heading northwest through the village of Prosperity. After the village, Route 18 separates from the concurrency and heads northward through the villages of Van Buren, Lagonda, and Gabby Heights as it approaches the city of Washington later. In Washington, Route 18 briefly overlaps with US 40, and the routes head west, intersect with the western terminus of PA Route 136, and then turn northwest.