As of the census of 2000, there were 13,876 people, 5,567 households, and 3,574 families residing in the city. The population density was 1,065.8 people per square mile (411.5/km²). There were 5,949 housing units at an average density of 457.0/sq mi (176.4/km²). The racial makeup of the city was 88.91% White, 0.20% African American, 8.56% Native American, 0.46% Asian, 0.02% Pacific Islander, 0.29% from other races, and 1.56% from two or more races. Hispanics or Latinos of any race were 1.25% of the population.
There were 5,567 households, out of which 32.9% had children under the age of 18 living with them, 51.6% were married couples living together, 9.5% had a female householder with no husband present, and 35.8% were non-families. 31.5% of all households were made up of individuals, and 10.7% had someone living alone who was 65 years of age or older. The average household size was 2.35, and the average family size was 2.96.
In the city, the population was spread out, with 27.2% under the age of 18, 6.5% from 18 to 24, 28.6% from 25 to 44, 23.6% from 45 to 64, and 14.1% who were 65 years of age or older. The median age was 38 years. For every 100 females, there were 90.5 males. For every 100 females age 18 and over, there were 85.4 males.
The median income for a household in the city was $42,962, and the median income for a family was $52,144. Males had a median income of $32,969 versus $22,865 for females. The per capita income for the city was $20,462. About 5.5% of families and 7.8% of the population were below the poverty line, including 7.9% of those under age 18 and 9.2% of those age 65 or over.
Airlines serving Pierre Regional Airport provide non-stop flights to Denver, Watertown, and Brookings, with continuing service to Minneapolis-St. Paul from Watertown.
The nearest interstate highway is Interstate 90, which is about 34 miles south of Pierre via U.S. Highway 83. Pierre is one of only five state capitals not served by an interstate highway. Dover, Delaware; Jefferson City, Missouri; Carson City, Nevada; and Juneau, Alaska, are the other four state capitals with this distinction.