Vardø (vär`dö), town (1995 pop. 3,016), Finnmark co., extreme NE Norway, on the island of Vardøya in the Arctic Ocean, near the entrance to the Varangerfjord. It is an ice-free port; fishing and seafood-processing are important to the economy. A joint U.S.-Norway radar tracking station is there. The town and island are connected to the mainland by an undersea tunnel. The northernmost fortress in the world was built at Vardø in 1307 and was rebuilt in the early 18th cent. Chartered in 1789, the town was long the center of a lively trade with Russia and Finland. Fridtjof Nansen used Vardø as the base for his important arctic expedition of 1893–96.