Boulder is a town in and the county seat of Jefferson County, Montana, United States. It is on the north bank of the Boulder River between Butte and Helena, slightly east of the Continental Divide, at the intersection of Interstate 15 and Montana Highway 69. The population was 1,183 at the 2010 census. It is part of the Helena Micropolitan Statistical Area.
As of the census of 2010, there were 1,183 people, 514 households, and 298 families residing in the city. The population density was 1,046.9 inhabitants per square mile (404.2/km). There were 565 housing units at an average density of 500.0 per square mile (193.1/km). The racial makeup of the city was 93.6% White, 1.8% Native American, 0.4% Asian, 0.3% from other races, and 3.9% from two or more races. Hispanic or Latino of any race were 2.9% of the population.
There were 514 households of which 23.2% had children under the age of 18 living with them, 42.8% were married couples living together, 9.1% had a female householder with no husband present, 6.0% had a male householder with no wife present, and 42.0% were non-families. 37.9% of all households were made up of individuals and 11.5% had someone living alone who was 65 years of age or older. The average household size was 2.15 and the average family size was 2.79.
The median age in the city was 43.7 years. 18.9% of residents were under the age of 18; 9.3% were between the ages of 18 and 24; 23.5% were from 25 to 44; 34.8% were from 45 to 64; and 13.6% were 65 years of age or older. The gender makeup of the city was 52.4% male and 47.6% female.
As of the census of 2000, there were 1,300 people, 508 households, and 316 families residing in the town. The population density was 1,142.7 people per square mile (440.3/km²). There were 568 housing units at an average density of 499.3 per square mile (192.4/km²). The racial makeup of the town was 94.23% White, 0.23% African American, 2.31% Native American, 0.69% Asian, 0.08% Pacific Islander, 0.31% from other races, and 2.15% from two or more races. Hispanic or Latino of any race were 1.15% of the population.
There were 508 households out of which 32.7% had children under the age of 18 living with them, 48.6% were married couples living together, 10.4% had a female householder with no husband present, and 37.6% were non-families. 34.8% of all households were made up of individuals and 12.8% had someone living alone who was 65 years of age or older. The average household size was 2.34 and the average family size was 3.04.
In the town, the population was spread out with 25.7% under the age of 18, 7.3% from 18 to 24, 30.8% from 25 to 44, 25.7% from 45 to 64, and 10.5% who were 65 years of age or older. The median age was 38 years. For every 100 females there were 103.1 males. For every 100 females age 18 and over, there were 102.5 males.
The median income for a household in the town was $29,276, and the median income for a family was $37,411. Males had a median income of $26,985 versus $22,500 for females. The per capita income for the town was $14,657. About 10.7% of families and 15.6% of the population were below the poverty line, including 19.7% of those under age 18 and 13.3% of those age 65 or over.