The Kpelle comprise more than 20% of the population and are the largest ethnic group in Liberia, residing mostly in Bong County and adjacent areas in central Liberia. Americo-Liberians, who are descendants of African American and West Indian, mostly Barbadian settlers, make up 2.5%. Congo people, descendants of repatriated Congo and Afro-Caribbean slaves who arrived in 1825, make up an estimated 2.5%. These latter two groups established political control in the 19th century which they kept well into the 20th century.