Past Sandy Creek, I-81 proceeds into Jefferson County, where it continues to travel across rural, undeveloped areas with only gentle elevation changes. US 11 crosses I-81 for the last time just north of the county line, connecting to the freeway and switching from the highway's west side to its east side. As a result, I-81 now passes west of several villages and large hamlets, all located directly on US 11. Connections to the communities are made by the primary east–west highways serving them, namely CR 90 for Mannsville; NY 193 for Pierrepont Manor; NY 178 for Adams; and NY 177 for Adams Center. At Adams Center, both I-81 and US 11 take on a more northeasterly routing, bringing them farther inland toward the city of Watertown. The final exit before the city itself leads to NY 232, a short connector between I-81 and Watertown Center, the southern extent of Watertown's suburbs.