The mountain range that runs parallel to the Rocky Mountains in the United States is the Sierra Nevada.

The Sierra Nevada is a prominent mountain range located primarily in eastern California, running approximately 400 miles from north to south. It is known for its stunning natural beauty, featuring dramatic granite cliffs, alpine lakes, and vast wilderness areas. Home to some of the highest peaks in the contiguous United States, including Mount Whitney, the Sierra Nevada offers diverse ecosystems and rich biodiversity. The range is also famous for its ancient giant sequoias, particularly in Sequoia and Kings Canyon National Parks. Outdoor enthusiasts flock to the Sierra Nevada for activities such as hiking, skiing, rock climbing, and camping, making it a vital destination for nature lovers and adventure seekers alike.