NY 19A, an easterly alternate route of NY 19, merges with NY 39, following the latter for to an unorthodox intersection southwest of the village. Heading west on NY 39, traffic is diverted onto a ramp leading to NY 19A, where commuters must turn left onto NY 19A to continue west on NY 39. Eastbound NY 39, however, has no such configuration, allowing eastbound traffic to remain on NY 39 through the intersection. Between Castile and the village of Perry, NY 39 assumes a slightly more northerly alignment, paralleling the edges of Silver Lake a half-mile to the northwest and Letchworth State Park to the southeast. Upon entering Perry, NY 39 shifts to a northeasterly alignment once again as it intersects NY 246 in the village center. East of the village, NY 39 switches counties for the final time as the road crosses into Livingston County.