Mandaree is located on the Fort Berthold Indian Reservation in the Mandan, Hidatsa and Arikara Nation. It is the home to current tribal chairman Tex Hall as well as being the primary physical center of the Mandan-Hidatsa community. It is noted nationally for its annual Pow-Wow as well as being the home of the Mandaree Singers, a world renowned tribal musical group.
There were 132 households out of which 59.8% had children under the age of 18 living with them, 34.1% were married couples living together, 40.9% had a female householder with no husband present, and 9.8% were non-families. 8.3% of all households were made up of individuals and 3.0% had someone living alone who was 65 years of age or older. The average household size was 4.23 and the average family size was 4.31.
In the CDP the population was spread out with 48.7% under the age of 18, 9.9% from 18 to 24, 23.8% from 25 to 44, 13.1% from 45 to 64, and 4.5% who were 65 years of age or older. The median age was 18 years. For every 100 females there were 97.2 males. For every 100 females age 18 and over, there were 88.2 males.
The median income for a household in the CDP was $24,167, and the median income for a family was $22,500. Males had a median income of $19,688 versus $17,604 for females. The per capita income for the CDP was $6,179. About 33.9% of families and 35.4% of the population were below the poverty line, including 38.9% of those under age 18 and 51.4% of those age 65 or over.