The _Illinois_ rises in the north-eastern parts of the state of that name, not more than thirty-five miles from the south-western extremity of Lake Michigan, and interlocking by a morass with the river Chicago, which empties into that lake. Its two main head-branches are Plein and Kankakee. Thirty miles from the junction of these rivers, enters Fox river from the north. Between this and the Vermilion, enter two or three inconsiderable rivers. The Vermilion is a considerable stream, which enters the Illinois from the south, two hundred and sixty miles above the Mississippi. Not far below this river, and two hundred and ten miles above the Mississippi, commences Peoria lake, which is no more than an enlargement of the river, two miles wide on an average, and twenty miles in length. Such is the depth and regularity of the bottom, that it has no perceptible current whatever. It is a beautiful sheet of water, with romantic shores, generally bounded by prairies; and no waters in the world furnish finer sport for the angler. On the north side of the Illinois, the rivers that enter on that shore have their courses, for the most part, in mountainous bluffs, which often approach near the river. For a great distance above its mouth, the river is almost as straight as a canal; has in summer scarcely a perceptible current, and the waters, though transparent, have a marshy taste to a degree to be almost unfit for use. The river is wide and deep; and, for the greater part of its width, is filled with aquatic weeds, to such an extent, that no person could swim among them. Only a few yards width, in the centre of the stream, is free from them. It enters the Mississippi through a deep forest, by a mouth four hundred yards wide. Perhaps no river of the western country has so fine a boatable navigation, for such a great distance; or waters a richer and more luxuriant tract of country. _Rock River_ is one of the most clear and beautiful tributaries of the Mississippi. It has its source beyond the northern limits of Illinois, and in a ridge of hills that separates between the waters of the Mississippi and those of Lake Michigan. On its waters are extensive and rich lead mines. Its general course is south-west, and it enters the Mississippi, not far above the commencement of the military bounty lands. Opposite the mouth of this river, in the Mississippi, is the beautiful island, called from the name of the river, and on which is a military station of the United States. _Kaskaskia River_ rises in the interior of Illinois, nearly interlocking with the waters of Lake Michigan. It has a course, in a south-west direction, of between two and three hundred miles, for the greater part of which course, in high stages of water, it is boatable. It runs through a fine and settled country, and empties into the Mississippi a few miles below the town of the same name.