Historic population statistics for Richland County and South Carolina are below:
Year: Richland / South Carolina
1900: 45,589 / 1,340,316
1910: 55,143 / 1,515,400
1920: 78,122 / 1,683,724
1930: 87,667 / 1,738,765
1940: 104,843 / 1,899,804
1950: 142,565 / 2,117,027
1960: 200,102 / 2,382,599
1970: 233,868 / 2,590,519
1980: 269,735 / 3,121,820
1990: 285,720 / 3,486,703
2000: 320,490 / 4,012,012
2010: 384,504 / 4,625,364
Source: U.S. Bureau of the Census (full report) "Population of States and Counties of the United States: 1790 - 1990."
Source: U.S. Bureau of the Census (extract) "South Carolina Population of Counties by Deccenial Census 1790 to 1990."
Source: U.S. Census Bureau State and County Quickfacts
Source: South Carolina County Population Changes on www.sciway.net.