Lone Tree is a home rule municipality in Douglas County, Colorado, United States. The city population was 10,218 at the 2010 United States Census, with an estimated population of 13,545 in 2014. Lone Tree is a part of the Denver-Aurora-Lakewood, CO Metropolitan Statistical Area.
Lone Tree is located on the northern border of Douglas County, directly adjacent to Arapahoe County. It is in what is called the "South Metro" area of Denver, located 18 miles (29 km) south of Denver's downtown.
The city annexed the University of Colorado South Denver campus, the former site of The Wildlife Experience, in 2017.
According to the United States Census Bureau, the city has a total area of 9.6 square miles (24.8 km2), all of it land.
As of the census of 2000, there were 4,873 people, 1,848 households, and 1,367 families residing in the city. The population density was 2,827.2 people per square mile (1,093.9/km²). There were 1,906 housing units at an average density of 1,105.8 per square mile (427.9/km²). The racial makeup of the city was 91.55% White, 1.48% African American, 0.25% Native American, 3.69% Asian, 0.04% Pacific Islander, 1.31% from other races, and 1.68% from two or more races. Hispanic or Latino of any race were 4.58% of the population.