Dawes Act. or. 1887, passed by the U.S. Congress to provide for the granting of landholdings (allotments, usually 160 acres/65 hectares) to individual Native Americans, replacing communal tribal holdings.Sponsored by U.S. Senator H. L. Dawes Dawes, Henry Laurens,1816–1903, U.S. Senator (1875–93), b. Cummington, Mass.r. 1887, passed by the U.S. Congress to provide for the granting of landholdings (allotments, usually 160 acres/65 hectares) to individual Native Americans, replacing communal tribal holdings.