The answer to the crossword puzzle is 'IDAHO, ' which is a state in the United States located in the northwestern region of the country. It is bordered by Montana, Wyoming, Nevada, Utah, Washington, and Oregon. IDAHO is known for its mountainous terrain, and it is home to the Rocky Mountains, the Bitterroot Range, and the Sawtooth Range. The capital of IDAHO is Boise, and the state is also home to several national parks, including Yellowstone National Park and Grand Teton National Park. IDAHO is often used as a substitute for an ID, such as when someone needs to prove their identity or age.