Orrin is a census-designated place and unincorporated community in Pierce County, North Dakota, United States. Its population was 22 as of the 2010 census.

Old Saint John Nepomocene Cemetery, Wrought-Iron Cross Site and St. Mathias Cemetery, Wrought-Iron Cross Site, both in or near Orrin, are listed on the National Register of Historic Places.

According to the United States Census Bureau, the CDP has a total area of 0.23 square miles (0.60 km), all land.

Historical population

Census	Pop.	Note	%±
2020	7		—
U.S. Decennial Census

As of the census of 2010, there were 22 people, 5 households, and 5 families residing in the CDP. The population density was 95.7 inhabitants per square mile (36.9/km). There were 17 housing units at an average density of 73.9 per square mile (28.5/km). The racial makeup of the CDP was 77.3% White, and 22.7% African American.

There were 5 households, of which 80.0% had children under the age of 18 living with them, 40.0% were married couples living together, 20.0% had a female householder with no husband present, and 40.0% had a male householder with no wife present. 0.0% of all households were made up of individuals. The average household size was 4.40 and the average family size was 4.20.

The median age in the CDP was 17.3 years. 59.1% of residents were under the age of 18; 4.5% were between the ages of 18 and 24; 18.2% were from 25 to 44; 9.1% were from 45 to 64; and 9.1% were 65 years of age or older. The gender makeup of the CDP was 63.6% male and 36.4% female.

It is within Rugby Public Schools, which operates Rugby High School.