"At each bend in the waterway, great stone walls seemed to block passage, only to open like gentle giant gates as the expedition drew near," Meriwether Lewis wrote on July 19, 1805. "“I shall call this place gates of the mountains."
If you’re interested in seeing the area described by Captain Lewis, you’ll find the Gates of the Mountains just north of Helena, Montana.
Holter Dam, constructed in 1918 about 10 miles downstream from the Gates of the Mountains, has raised water levels in the Gates area by about 30 feet. Yet, it’s easy to be a part of the Expedition, seeing the limestone walls the way the men of the Corps saw them.