Montana ranked 44th in population in the US with an estimated total of 909,453 in 2002, an increase of 0.8% since 2000. Between 1990 and 2000, Montana's population grew from 799,065 to 902,195, an increase of 12.9%. The population is projected to reach 1,006,000 by 2005 and 1.1 million by 2025. The population density in 2000 was 6.2 persons per sq mi, the 3rd-lowest in the country.

In 2000, the median age of all Montana residents was 37.5. In the same year, 25.5% of the populace were under the age of 18 while 13.4% were age 65 or older.

Montana had no cities with populations exceeding 100,000 in 2002. The largest cities and their estimated populations are Billings, 89,847, and Great Falls, 56,690.