Idaho ranked 39th in population in the US with an estimated total of 1,341,131 in 2002, an increase of 3.6% since 2000. Between 1990 and 2000, Idaho's population grew from 1,006,749 to 1,293,953, an increase of 28.5%—the 5th-largest percentage gain among the 50 states for this period. The population is projected to reach 1,480,000 by 2005 and 1.7 million by 2025. Population density in 2000 was 15.6 persons per sq mi.
The median age was 33.2 in 2000. Nearly 28.5% of the population were under age 18 while 11.3% were age 65 or older. Although no part of Idaho except Boise is genuinely urban, even Boise does not have a large central city. Boise's estimated 2002 population was 189,847; Boise's metropolitan area (Ada County) had an estimated 1999 population of 407,844. Other major cities with large populations include Pocatello, Idaho Falls, Nampa, Lewiston, and Twin Falls.