Altamont is a city in Effingham County, Illinois, United States. The population was 2,283 at the 2000 census.
Altamont is located at 39°3′25″N 88°44′51″W / 39.05694°N 88.7475°W / 39.05694; -88.7475 (39.0569861, -88.7474670 ). According to the United States Census Bureau, the city has a total area of 1.3 square miles (3.4 km²), all of it land.
As of the census of 2000, there were 2,283 people, 899 households, and 608 families residing in the city. The population density was 1,751.6 inhabitants per square mile (678.1/km²). There were 955 housing units at an average density of 732.7 per square mile (283.6/km²). The racial makeup of the city was 99.30% White, 0.09% African American, 0.09% Native American, Pacific Islander, and 0.53% from two or more races. Hispanic or Latino of any race were 0.35% of the population.