Pembina is the oldest community in The Dakotas A fur-trading post was established on the site of present-day Pembina in 1797 and the first permanent settlement started in 1812. The first post office in present-day North Dakota was established in Pembina in 1851. Pembina is at the northern end of Interstate 29, on the Canada-United States border. It is a significant crossing for road traffic headed to and from Winnipeg, Manitoba and is one of three 24-hour ports of entry in North Dakota.