Houlton is the county seat for Aroostook County, and as such its nickname is the "Shire Town" and the Houlton High School sports teams are named "The Shiretowners". The Meduxnekeag River flows through the heart of the town, and the border with the Canadian province of New Brunswick is three miles east of the town's center. Houlton was the home of Ricker College which closed in 1978.
Primary settlement and center of the town is designated as CDP with same name, Houlton.
As of the census of 2000, there were 6,476 people, 2,677 households, and 1,654 families residing in the town. The population density was 176.2 people per square mile (68.0/km²). There were 2,994 housing units at an average density of 31.5 persons/km² (81.5 persons/sq mi). The racial makeup of the town was 94.19% White, 0.29% African American, 4.23% Native American, 0.48% Asian, 0.08% Pacific Islander, 0.09% from other races, and 0.63% from two or more races. 0.43% of the population were Hispanic or Latino of any race.
There were 1,677 households out of which 29.5% had children under the age of 18 living with them, 47.4% were married couples living together, 11.0% have a woman whose husband does not live with her, and 38.2% were non-families. 34.3% of all households were made up of individuals and 18.0% had someone living alone who was 65 years of age or older. The average household size was 2.29 and the average family size was 2.94.
In the town the population was spread out with 23.7% under the age of 18, 7.1% from 18 to 24, 26.0% from 25 to 44, 21.9% from 45 to 64, and 21.3% who were 65 years of age or older. The median age was 40 years. For every 100 females there were 87.5 males. For every 100 females age 18 and over, there were 82.4 males.
The median income for a household in the town was $26,212, and the median income for a family was $34,812. Males had a median income of $27,623 versus $20,991 for females. The per capita income for the town was $14,007. 17.7% of the population and 13.5% of families were below the poverty line. Out of the total people living in poverty, 21.0% are under the age of 18 and 15.8% are 65 or older.