Loveland Pass, located in Colorado, is a high mountain pass within the Rocky Mountains.

Loveland Pass is a high-altitude mountain pass in the Rocky Mountains of Colorado, situated west of Denver. It's known for its scenic views and challenging driving conditions, especially during winter. While Donner Pass is in the Sierra Nevada, Snoqualmie Pass is in the Cascade Range, and Cajon Pass is in Southern California's San Bernardino Mountains, Loveland Pass is distinctly located within the Rockies, making it the correct answer.