CHESTER, a city of the United States, in the county of Delaware, Pennsylvania, on the right bank of the Delaware River, 10 miles south-west of Philadelphia by the railway to Wilmington. It has five or six churches, two high schools, and a national hall, and carries on the manufacture of cotton and woollen goods, machinery, and carriages. Founded by the Swedes in 1643 under the name of Upland, it ranks as the oldest town in the State, and was the seat of the provisional assembly held by Penn in 1682. From that date till the formation of Delaware county in 1789, it was the chief town of the county of Chester,—a position now held by the city of West Chester. Population in 1850, 1667 ; and in 1870, 9485.