Kentucky ranked 26th in population in the US with an estimated total of 4,092,891 in 2002, an increase of 1.3% since 2000. Between 1990 and 2000, Kentucky's population grew from 3,685,296 to 4,041,769, an increase of 9.7%. The population is projected to reach 4.3 million by 2025. The population density in 2000 was 101.7 persons per sq mi.
In 2000 the median age was 35.9. Persons under 18 years old accounted for 24.6% of the population while 12.5% were age 65 or older.
During the early decades of settlement, population grew rapidly, from a few hundred in 1780 to 564,317 in 1820, by which time Kentucky was the 6th most populous state. By 1900, however, when the population was 2,147,174, growth had slowed considerably. For most of the 20th century, Kentucky's growth rate was significantly slower than the national average.
As of 2002, Lexington had replaced Louisville as the state's largest city. Lexington-Fayette had an estimated population of 263,618, compared with 251,399 for Louisville. Owensboro, with over 50,000 residents, was the state's 3rd most populous city. The population of the Louisville (Ky.-Ind.) metropolitan area was estimated at 1,005,849 in 1999; the Lexington metropolitan area had 455,617, up from 435,736 in 1995.