NDSU Extension in Williams County gives local residents easy access to the resources and expertise of North Dakota State University. The Williams County Extension Office is now open to the public effective June 15, 2020. PHYSICAL ADDRESS - (Please use for NON-USPS Deliveries) NDSU Extension/Williams County 302 East Broadway (across from the Law Enforcement Center) Williston, ND 58801 USPS - ADDRESS NDSU EXTENSION-WILLIAMS COUNTY PO Box 1109 Williston, ND 58802-1109 Telephone: (701) 577-4595 [Call: (701) 577-4595] Fax: (701) 577-4597 [Call: (701) 577-4597] Email: mindy.sigvaldsen@ndsu.edu