ROCK ISLAND a city of the United States, the capital of Rock Island county, Illinois, is situated opposite Davenport on the left bank of the Mississippi, about 3 miles above the mouth of the Rock river and at the foot of the Upper Rapids, which extend for about 16 miles. Distant by rail 181 miles west of Chicago and 247 miles north of St Louis, Rock Island is one of the great centres of railroad and river traffic. With Davenport (in Iowa) it is connected by a two-story road and railway bridge constructed by the Government in 1870. Among the public buildings are a large public library and St Augustana College, founded by the Swedish Lutherans. Glassworks, a plough factory, a distillery, flour-mills, and a stove factory are the principal industrial establishments. The city, however, is best known from the great national arsenal situated on the island from which it derives its name. This island is a ridge of limestone rock about 3 miles long and with an area of 960 acres. As the site of Fort Armstrong it became known in the Black Hawk War; the prison was used for the detention of Confederate prisoners during the Civil War; and since that date the Government has constructed the present extensive works, intended to be the central United States armoury. There are ten vast stone workshops, each with a stone house in the rear, as well as officers’ quarters, offices, &c. The population of Rock Island city was 5130 in 1860, 7890 in 1870, and 11,659 in 1880. Its charter dates from 1849.