DE 100 continues north through wooded areas with fields and homes, crossing the East Penn Railroad line again at-grade. The road runs through Montchanin and passes to the east of the Wilmington Country Club before crossing the railroad tracks again at-grade and coming to an employee entrance to the Winterthur Museum and Country Estate to the west. The route intersects the western terminus of DE 92 and Adams Dam Road on the western edge of Brandywine Creek State Park. At this point, DE 92 continues straight to the northeast and DE 100 turns north to remain on Montchanin Road, heading across Wilson Run. The road crosses under the East Penn Railroad again and curves northwest, coming to an intersection with Center Meeting Road/Smith Bridge Road. DE 100 bends to the north again before reaching its northern terminus at the Pennsylvania border, where the road continues into that state as SR 3100 (Chadds Ford Road), an unsigned quadrant route. The Montchanin Road portion of DE 100 is part of the Brandywine Valley National Scenic Byway, a National Scenic Byway and Delaware Byway.