Custer is a census-designated place (CDP) in Yellowstone County, Montana, United States. The population was 145 at the 2000 census.
Custer is located at 46°7′44″N 107°33′23″W / 46.12889°N 107.55639°W / 46.12889; -107.55639 (46.128870, -107.556302).
According to the United States Census Bureau, the CDP has a total area of 0.3 square miles (0.78 km), all of it land.
As of the census of 2000, there were 145 people, 68 households, and 39 families residing in the CDP. The population density was 563.7 people per square mile (215.3/km²). There were 79 housing units at an average density of 307.1 per square mile (117.3/km²). The racial makeup of the CDP was 95.86% White, 1.38% from other races, and 2.76% from two or more races. Hispanic or Latino of any race were 1.38% of the population.
There were 68 households out of which 25.0% had children under the age of 18 living with them, 51.5% were married couples living together, 5.9% had a female householder with no husband present, and 42.6% were non-families. 39.7% of all households were made up of individuals and 13.2% had someone living alone who was 65 years of age or older. The average household size was 2.13 and the average family size was 2.87.
In the CDP, the population was spread out with 21.4% under the age of 18, 4.1% from 18 to 24, 21.4% from 25 to 44, 37.2% from 45 to 64, and 15.9% who were 65 years of age or older. The median age was 46 years. For every 100 females, there were 110.1 males. For every 100 females age 18 and over, there were 123.5 males.
The median income for a household in the CDP was $26,944, and the median income for a family was $43,000. Males had a median income of $21,250 versus $0 for females. The per capita income for the CDP was $18,532. 1.4% of the population lived below the poverty line, this percentage was not made up of families, those under 18 or over 64.