Welcome to the official website of Jefferson County New York Search 32℉ Light Snow DEPARTMENTS GOVERNMENT SERVICES RESIDENTS VISITING BUSINESSES I WANT TO... COVID 19 INFO Popular Links List of popular links for easy reference. VIEW LINKS Department Directory Portal to Jefferson County Departments. VIEW DEPARTMENTS Jefferson County New York 175 Arsenal Street Watertown, NY 13601 Phone: (315)785-3000 Ⓒ 2021 Jefferson County, New York Site by EvoGov