ADAMS, the name of six different counties in the United States of America. 1st, in Pennsylvania, population, in 1850, 25,988; 2d, in the southern district of Mississippi, population, 18,621; 3d, in Ohio, population, 18,943; 4th, in Indiana, population, 5774; 5th, in Illinois, population, 26,537; 6th, in Wisconsin, population, 187.