Portland is a city in Traill County, North Dakota, United States. The population was 606 at the 2010 census.
Portland is the smaller neighbor of nearby Mayville.
The first settlement at Portland was made in 1871. Portland was laid out and platted in 1881 when the railroad was extended to that point. A post office has been in operation at Portland since 1882.
Portland is located at 47°30′2″N 97°22′19″W (47.500451, -97.371960).
According to the United States Census Bureau, the city has a total area of 0.86 square miles (2.23 km2), all of it land.
As of the census of 2010, there were 606 people, 279 households, and 170 families residing in the city. The population density was 704.7 inhabitants per square mile (272.1/km2). There were 297 housing units at an average density of 345.3 per square mile (133.3/km2). The racial makeup of the city was 95.0% White, 0.7% African American, 1.5% Native American, 0.5% Asian, 1.3% from other races, and 1.0% from two or more races. Hispanic or Latino of any race were 2.6% of the population.
There were 279 households of which 25.1% had children under the age of 18 living with them, 50.2% were married couples living together, 7.5% had a female householder with no husband present, 3.2% had a male householder with no wife present, and 39.1% were non-families.