The Great Plains meet the Rocky Mountains in Wyoming. The state is a great plateau broken by a number of mountain ranges. In the northwest are the Absaroka, Owl Creek, Gros Ventre, Wind River and the Teton ranges. In the north central are the Big Horn Mountains; in the northeast, the Black Hills; and in the southern region the Laramie, Medicine Bow and Sierra Madre ranges.

Wyoming is an arid state with much of the land receiving less than 10 inches (25 cm) of rainfall per year. Consequently, the land supports few opportunities for farming. Ranching is widespread, especially in areas near the numerous mountain chains. The Snowy Range in the south central part of the state is an extension of the Colorado Rockies in both geology and appearance. The Wind River Range in the west central part of the state is remote and includes Gannett Peak, the highest peak in the state.

The Big Horn Mountains in the north central portion are somewhat isolated from the bulk of the Rocky Mountains. Old Faithful GeyserThe Teton Range in the northwest extends for 50 miles (80 km) and represents the most impressive section of mountains in the state. It is home to Grand Teton, the second highest peak in Wyoming, and to Grand Teton National Park, which preserves the most scenic section of the Teton range.

Several rivers begin or flow through the state, including the Yellowstone River, Powder River, and the Snake River. The Continental Divide forks in the south central part of the state. The waters that flow or precipitate into this area, known as the Great Divide Basin, do not flow to any ocean. Instead, because of the overall aridity of Wyoming, they simply sink into the soil or evaporate. Rivers east of the Divide drain into the Missouri River Basin and eventually the Atlantic Ocean. They are the Platte, Wind, Big Horn and the Yellowstone rivers. The Snake River in northwest Wyoming eventually drains into the Columbia River and the Pacific Ocean, as does the Green River through the Colorado River Basin.