Niwot is a census-designated place (CDP) in Boulder County, Colorado, United States. It is thirty-three miles (53 km), by road, northwest of the Colorado State Capitol in Denver. The population was 4,006 at the 2010 census. The Niwot Post Office has the ZIP Code 80544.
Niwot is located at 40°5′59″N 105°9′37″W / 40.09972°N 105.16028°W / 40.09972; -105.16028 (40.099855, -105.160305), along State Highway 119, halfway between Boulder and Longmont.
According to the United States Census Bureau, the CDP has a total area of 4.0 square miles (10.4 km), of which 0.008 square miles (0.02 km), or 0.23%, is water.
As of the census of 2000, there were 4,160 people, 1,502 households, and 1,094 families residing in the CDP. The population density was 1,026.4 people per square mile (396.6/km²). There were 1,546 housing units at an average density of 381.4 per square mile (147.4/km²). The racial makeup of the CDP was 94.52% White, 0.48% African American, 0.38% Native American, 2.16% Asian, 0.02% Pacific Islander, 1.06% from other races, and 1.37% from two or more races. Hispanic or Latino of any race were 3.39% of the population.
There were 1,502 households out of which 40.8% had children under the age of 18 living with them, 65.0% were married couples living together, 5.9% had a female householder with no husband present, and 27.1% were non-families. 21.4% of all households were made up of individuals and 3.3% had someone living alone who was 65 years of age or older. The average household size was 2.66 and the average family size was 3.15.
In the CDP, the population was spread out with 28.5% under the age of 18, 4.8% from 18 to 24, 29.5% from 25 to 44, 31.3% from 45 to 64, and 5.9% who were 65 years of age or older. The median age was 40 years. For every 100 females, there were 102.8 males. For every 100 females age 18 and over, there were 103.3 males.
The median income for a household in the CDP was $86,914, and the median income for a family was $100,120. Males had a median income of $81,813 versus $39,279 for females. The per capita income for the CDP was $39,943. About 2.5% of families and 5.6% of the population were below the poverty line, including 2.1% of those under age 18 and 2.0% of those age 65 or over.