Final answer:
Montana is the state with the Rockies, the Bitterroot Range coming from Idaho, the Lewis Range, and the Big Belt Mountains.
Step-by-step explanation:
The state with the Rockies in the western portion, Bitterroot Range in Idaho coming into it, and the Lewis Range as part of the Rockies along with the Big Belt Mountains, is Montana. The Rocky Mountains are an immense range that includes a variety of subranges and spans multiple U.S. states. Montana, in particular, is known for its diverse geological features such as the Rocky Mountains and the Bitterroot Range, which extends from Idaho into western Montana. The Lewis Range is also a notable feature within the Rocky Mountains, primarily located in Montana, which includes Glacier National Park. The Big Belt Mountains are a subrange of the Rockies situated in Montana as well. The state's scenic landscapes and national parks draw many visitors and, as mentioned, Montana's population is growing although not as quickly as some other states in the Mountain West such as Nevada, Utah, and Idaho. Montana's geography and natural features are quintessential attributes of what the Mountain West represents.