Gardiner is a census-designated place (CDP) in Park County, Montana, United States, along the 45th parallel. The population was 875 at the 2010 census.
Gardiner is located at 45°2′13″N 110°42′50″W / 45.03694°N 110.71389°W / 45.03694; -110.71389 (Gardiner, Montana)Coordinates: 45°2′13″N 110°42′50″W / 45.03694°N 110.71389°W / 45.03694; -110.71389 (Gardiner, Montana) (45.036837, -110.713768).
According to the United States Census Bureau, the CDP has a total area of 3.9 square miles (10 km), of which, 3.8 square miles (9.8 km) of it is land and 0.1 square miles (0.26 km) of it (2.32%) is water. Quite a few of the residents either work in, or have at one time, worked in Yellowstone.
As of the census of 2000, there were 851 people, 435 households, and 210 families residing in the CDP. The population density was 224.9 people per square mile (86.9/km²). There were 497 housing units at an average density of 131.3 per square mile (50.8/km²). The racial makeup of the CDP was 97.30% White, 0.35% African American, 1.41% Native American, 0.24% Asian, 0.12% from other races, and 0.59% from two or more races. Hispanic or Latino of any race were 0.47% of the population.
There were 435 households, of which 22.1% had children under the age of 18 living with them, 40.0% were married couples living together, 5.7% had a female householder with no husband present, and 51.5% were non-families. 43.2% of all households were made up of individuals and 4.8% had someone living alone who was 65 years of age or older. The average household size was 1.96 people and the average family size 2.73.
In the CDP, the age of the population was spread out with 20.8% under the age of 18, 2.9% from 18 to 24, 40.5% from 25 to 44, 28.0% from 45 to 64, and 7.8% who were 65 years of age or older. The median age was 39 years. For every 100 females, there were 96.5 males. For every 100 females age 18 and over, there were 99.4 males.
The median income for a household in the CDP was $30,125, and the median income for a family was $46,071. Males had a median income of $30,240 versus $17,614 for females. The per capita income for the CDP was $17,810. About 3.4% of families and 8.2% of the population were below the poverty line, including 4.8% of those under age 18 and none of those age 65 or over.