Although they are often linked in people's minds, Yellowstone and Grand Teton national parks couldn't be much more different. One is an immense wilderness plateau that sits atop a caldera seething with molten lava; the other is a striking set of peaks rising from a broad river plain. One encloses some of the most remote backcountry in the Lower 48 and provides crucial habitat for rare species such as grizzly bears and wolves; the other is only a quick drive away from a chic resort town and includes an airport and grazing cattle in its mixed-use approach.
What they do share is the affection of millions of visitors who come here annually to renew their ties to nature through the parks' shining mountains, alpine lakes, majestic elk, and astonishing geysers.
Unfortunately, mining, logging, and housing developments have impacted the area known as the Greater Yellowstone Ecosystem that surrounds the parks. The ecosystem is an interdependent system of watersheds, mountain ranges, wildlife habitat, and other components extending beyond the two parks into seven national forests, an Indian reservation, three national wildlife refuges, and nearly a million acres of private land. To put it into perspective, the ecosystem's 18 million acres span an area as big as Connecticut, Rhode Island, and Delaware combined. It is one of the largest intact temperate ecosystems on the planet.
It's also a massive and important source of water. West of the Continental Divide, snowmelt trickles into creeks, streams, and rivers through Yellowstone before draining into the Snake River, traveling through Grand Teton National Park and Idaho, and running into the Columbia River, which winds its way west through Oregon and into the Pacific Ocean.
Water on the eastern slopes of the divide passes through Yellowstone in the form of the Madison and Gallatin rivers, which meet the Jefferson River west of Bozeman, Montana, merging into the Missouri. Then, as the song lyrics tell us, the Mighty Mo runs "down the Mississippi to the Gulf of Mexico."
As if that weren't enough, the headwaters of the Yellowstone River are in the remote Thorofare country south of Yellowstone Lake. After running north the length of the park, the Yellowstone meanders across Montana as the longest undammed river in America, until it converges with the Missouri in North Dakota.
