The wild, trackless prairie of Lewis and Clark's time is now the site of the thriving town of Great Falls, which has a population of ten thousand.
Here is a lucid and connected account of the falls and rapids, discovered and described by Lewis and Clark: "This river is three hundred yards wide at the point where it receives the waters of Medicine (Sun) River, which is one hundred and thirty-seven yards in width.

The united current continues three hundred and twenty-eight poles to a small rapid on the north side, from which it gradually widens to fourteen hundred yards, and at the distance of five hundred and forty-eight poles reaches the head of the rapids, narrowing as it approaches them.

Here the hills on the north, which had withdrawn from the bank, closely border the river, which, for the space of three hundred and twenty poles, makes its way over the rocks, with a descent of thirty feet.

In this course the current is contracted to five hundred and eighty yards, and after throwing itself over a small pitch of five feet, forms a beautiful cascade of twenty-six feet five inches; this does not, however, fall immediately or perpendicularly, being stopped by a part of the rock, which projects at about one-third of the distance.
After descending this fall, and passing the cottonwood island on which the eagle has fixed her nest, the river goes on for five hundred and thirty-two poles over rapids and little falls, the estimated descent of which is thirteen and one-half feet, till it is joined by a large fountain boiling up underneath the rocks near the edge of the river, into which it falls with a cascade of eight feet.

The water of this fountain is of the most perfect clearness, and of rather a bluish cast; and, even after falling into the Missouri, it preserves its color for half a mile.