The Town of Johnstown is a Home Rule Municipality in Weld and Larimer counties in the U.S. state of Colorado. The population was 9,887 at the 2010 United States Census.
Johnstown is located just west of the confluence of the Big Thompson River and the Little Thompson River. Greeley is about ten miles to the east-northeast and Loveland is approximately nine miles to the northwest.
According to the United States Census Bureau, the town in 2010 had a total area of 13.52 square miles (35.0 km).
As of the census of 2010, there were 9,887 people, 3,356 households, and 2,738 families residing in the town. The population density was 731.3 people per square mile (282.5/km²). There were 3,554 housing units at an average density of 262.9 per square mile (101.5/km²). The racial makeup of the town was 91.7% White, 0.8% African American, 1.4% Native American, 1.4% Asian, and 7.3% from other races. Hispanic or Latino of any race were 16.8% of the population.
There were 3,356 households out of which 42.8% had children under the age of 18 living with them, 69.7% were married couples living together, 7.0% had a female householder with no husband present, and 18.4% were non-families. 13.8% of all households were made up of individuals and 4.0% had someone living alone who was 65 years of age or older. The average household size was 2.95 and the average family size was 3.25.
In the town, the population was spread out with 31.2% under the age of 18, 5.8% from 18 to 24, 32.3% from 25 to 44, 22.0% from 45 to 64, and 8.7% who were 65 years of age or older. The median age was 33.7 years. For every 100 females, there were 101.7 males.
The median income for a household in the town was $69,919, and the median income for a family was $75,000. Males had a median income of $55,426 versus $40,536 for females. The per capita income for the town was $26,324. About 5.4% of families and 5.9% of the population were below the poverty line, including 6.4% of those under age 18 and 5.1% of those age 65 or over.