OTHER CITIES OF ILLINOIS The area and its divisions.—The cities of the state not treated in previous chapters will be included in this chapter. The region includes those portions of the state bordering on the Mississippi, Ohio, and Wabash rivers, and extending back to the divides between these basins and the Illinois Basin.
It comprises the drainage basins of the Rock, Kaskaskia, Big Muddy, Ohio, and Wabash rivers, and also the minor basins of the Mississippi. The total area is 31,23S square miles, or about 56 per cent of the area of the state.
Cities of northwest ern Illinois. —The northwestern part of the state, between the Rock River Basin and the Mississippi River, is drained directly into the Mississippi through small streams, the Galena River being most important.
Galena (4,835), the county seat of Jo Daviess County, is the largest city of this area. It is the center of the lead- and zinc-mining of Illinois. Savanna (3,691), the largest city of Carroll County, is situated on the Mississippi River. Mount Carroll (1,759) is the county seat of Car roll County. Fulton (2,174), in Whiteside County, is on the Mis sissippi opposite Clin ton, Iowa (25,577).
Cities of the Rock River Basin.—The Rock River Basin in Illinois contains 5,310 square miles, or nearly 10 per cent of the area of the state. Twelve cities having a popula tion of 2,500 or more are located within the basin and three others are situated at the edge of the basin on the Missis sippi River. The total population of these fif teen cities in 1910 was 164,05S, and important increases have taken place since that date.
Freeport (17,567), the county seat of Stephenson County, is located on the Peca tonica River, a tribu tary of Rock River. It is an important railroad and manufacturing cen ter with 48 per cent of the population of Stephenson County.
Rockford (45,401), the county seat of Winnebago County, is on the Rock River. It is the fifth city in the state in popu lation, and 72 per cent of the people of Winnebago County live in Rockford.
Camp Grant was established on the east side of Rock River just below Rockford soon after the United States entered the world-war against Germany. In a few weeks' time a military city was constructed capable of housing a population equal to that of the city of Rockford. From September, 1917, when the cantonment was first opened, to the close of the war, Camp Grant was the busiest center of activity in Rock River Basin. Here the soldiers were given the intensive training • necessary to make them the best fighters of modern war fare. The topography of the region of Camp Grant presents features of some military impor tance.
If the area is looked upon from the point of view of mili tary operations, there are some significant features, though none of a command ing character.
The Rock, the Peca tonica, the Kishwaukee, and the Sugar rivers all are large enough to interfere with the crossing of men or wheels, except where they are bridged. Bridges are destroyed easily, so that problems of stream crossings are serious, as the Austrians found in their early attempts (1914) to cross the Save and the Danube, into Serbia. The Rock, though a small stream as compared with some of those which have played an important part in the European conflict, is too large in most places to be forded at any time.
The valleys of some of the larger rivers of western France, as the Somme, have low flood plains which offer problems similar to those of the Pecatonica.
The Kishwaukee and Rock rivers afford opportunity for the study of problems in crossing streams where bridges are wanting, but where the bottom is firm. The valley of the Pecatonica offers excellent opportunity for the study of the many problems which armies might encounter in the field, in crossing wet, marshy and flooded tracts, and in crossing streams with soft, muddy bottoms.
The utilization of steep slopes can he studied to good advantage along the Kishwaukee above Camp, and along the Rock below the Kishwaukee.