Now in the Wyoming County town of Genesee Falls, the landscape surrounding NY 19A becomes more forested as the highway approaches Letchworth State Park. NY 19A continues along the western bank of the Genesee River to the hamlet of Portageville, a riverside community located at the southern tip of the park. Here, NY 19A intersects NY 436 in the center of the community. NY 436 joins NY 19A here, and the two routes leave Portageville to the northwest. For the most part, NY 19A and NY 436 pass southwest of Letchworth State Park; however, they do connect to the park by way of a local park road just north of Portageville. In this area, the Genesee River turns northeast to flow through the park instead.