Utah County is part of the Provo-Orem Metropolitan Statistical Area.
As of the census of 2000, there were 368,536 people, 99,937 households, and 80,749 families residing in the county. The population density was 184 people per square mile (71/km²). There were 104,315 housing units at an average density of 52 per square mile (20/km²). The racial makeup of the county was 92.36% White, 0.30% Black or African American, 0.60% Native American, 1.06% Asian, 0.58% Pacific Islander, 3.25% from other races, and 1.85% from two or more races. 7.00% of the population were Hispanic or Latino of any race. The top 5 Ethnic groups in Utah County are:
By 2005 non-Hispanic whites were 87.7% of the county population. 0.4% of the population was African-American. The Native American population was holding steady at 0.6%, but it should be remembered with the county population growing quite fast, this meant the number of Native Americans was on the rise. Pacific Islanders were still 0.6% of the population. Latinos were now 8.4% of the population.
In 2000 There were 99,937 households out of which 48.30% had children under the age of 18 living with them, 69.80% were married couples living together, 8.00% had a female householder with no husband present, and 19.20% were non-families. 11.20% of all households were made up of individuals and 4.70% had someone living alone who was 65 years of age or older. The average household size was 3.59 and the average family size was 3.86.
In the county, the population was spread out with 34.10% under the age of 18, 21.00% from 18 to 24, 25.90% from 25 to 44, 12.70% from 45 to 64, and 6.40% who were 65 years of age or older. The median age was 23 years. For every 100 females there were 98.30 males. For every 100 females age 18 and over, there were 94.50 males.
The median income for a household in the county was $45,833, and the median income for a family was $50,196. Males had a median income of $37,878 versus $22,656 for females. The per capita income for the county was $15,557. About 6.80% of families and 12.00% of the population were below the poverty line, including 8.40% of those under age 18 and 4.80% of those age 65 or over.
By 2006 the population had risen 26.1% to 464,760.
About 88% of Utah County residents are LDS. "Happy Valley" is a common nickname for the region (also known as Utah Valley). The term is sometimes used in a pejorative or ironic sense.