SANGAMON or SANGAMO COUNTY, situated in the central part of Illinois, and traversed by Sangamon river.  Area, 900 square miles.  Face of the country, even; soil, rich.  Seat of Justice, Springfield, which is also the state capital.  Pop. in 1830, 12,960; in 1840, 14,716; in 1850, 19,228.

FRANKLIN COUNTY, situated in the southerly part of Illinois. Area, 866 square miles. Face of the country generally level; soil productive. Seat of justice, Benton. Pop. in 1820, 1,763; in 1830, 4,083; in 1840, 3,682; in 1850, 5,681.

SALINE COUNTY, situated in the southerly part of Illinois.  Area,     square miles. Seat of justice, Raleigh. Pop. in 1850, 5,558.

FAYETTE COUNTY, situated toward the central part of Illinois, and traversed by the Kaskaskia River. Area, 648 square miles. Seat of justice, Vandalia. Pop. in 1830, 2,704; in 1840, 6,328; in 1850, 8,075.

EFFINGHAM COUNTY, situated toward the southeasterly part of Illinois. Area, 486 square miles. Soil of middling quality. Seat of justice, Ewington. Pop in 1840, 1,675; in 1850, 3,799.

EDWARDS COUNTY, situated in the southeasterly part of Illinois. Area, 200 square miles. Face of the country undulating; soil generally fertile. Seat of justice, Albion. Pop. in 1820, 3,444; in 1830, 1,649; in 1840, 3,070; in 1850, 3,524.

EDGAR COUNTY, situated on the easterly boundary of Illinois. Area, 630 square miles. Soil rich. Seat of justice, Paris. Pop. in 1830, 4,076; in 1840, 8,335; in 1850, 10,692.

DEKALB COUNTY, situated in the northern part of Illinois. Area, 648 square miles. Seat of justice, Sycamore. Pop. in 1840, 1,697; in 1850, 7,450.

DE WITT COUNTY, situated near the central part of Illinois. Area, ----- square miles. Seat of justice, Clinton. Pop. in 1850, 5,002.