The term "Alabama Fever" was used as early as 1817, during the Alabama Territory period (1817-1819). Settlers came primarily from the seaboard Old South states such as Virginia, North Carolina, South Carolina and eastern Georgia. There, land fertility had declined to a point that cotton cultivation had become difficult. Alabama had a population estimated at under 10,000 people in 1810, but it had increased to more than 300,000 people by 1830. Most Native American tribes were completely removed from the state within a few years of the passage of the Indian Removal Act by the United States Congress in 1830. By 1860 the population had increased to a total of 964,201 people, of which 435,080 were enslaved African Americans and 2,690 were free people of color.