Alabama ranked 23rd in population among the 50 states with an estimated total of 4,486,508 in 2002, an increase of 0.9% since 2000. Between 1990 and 2000, Alabama's population grew from 4,040,587 to 4,447,100, an increase of 10.1%. The population is projected to reach 4,631,000 by 2005 and 5,200,000 by 2025.
In 2000 the median age was 35.8%. Persons under 18 years old accounted for 25.3% of the population, while 13% were age 65 or older.
Alabama experienced its greatest population growth between 1810 and 1820, following the defeat of the Creek Nation by General Andrew Jackson and his troops. Population in what is now Alabama boomed from 9,046 in 1810 to 127,901 in 1820, as migrants from older states on the eastern seaboard poured into the territory formerly occupied by the Creek Indians. Thousands of farmers, hoping to find fertile land or to become wealthy cotton planters, brought their families and often their slaves into the young state, more than doubling Alabama's population between 1820 and 1830. By 1860, Alabama had almost 1,000,000 residents, nearly one-half of whom were black slaves. The Civil War brought Alabama's population growth almost to a standstill, largely because of heavy losses on the battlefield. The total population gain between 1860 and 1870 was only about 30,000 whereas between 1870 and 1970, Alabama's population rose 150,000–300,000 every decade. During the 1980s the population increased 148,000.
In 2000, Alabama had a population density of 87.6 persons per sq mi. First in size among Alabama's metropolitan areas comes greater Birmingham, which had an estimated 915,000 residents in July 1999. Other major metropolitan areas were greater Mobile, 535,472; greater Montgomery, 322,441; and greater Huntsville, 343,418. The city of Birmingham proper was Alabama's largest city, with an estimated 239,416 residents in 2002; Montgomery had 201,425, and Mobile had 194,862.