Portal is a city in Burke County, North Dakota, United States. The population was 125 at the 2020 census. Portal was founded in 1893. …Portal is a city in Burke County, North Dakota, United States. The population was 125 at the 2020 census. Portal was founded in 1893. Portal sits along the Canada–United States border and is a major port of entry border crossing for road and rail traffic. North Portal, Saskatchewan is just over the border north of Portal and adjacent to it. It is one of three year-round, 24-hour ports in North Dakota.