The Sierra Nevada mountains are on the east side of the valley. These mountains are very tall and steep. Lots of rivers and streams flow off the Sierra Nevada. The highest mountain in the Sierra Nevada is Mount Whitney (14,495') which is also the tallest mountain in California and the rest of the United States (except for Alaska and Hawaii). On the west side, there is the California Coast Ranges, an extension of the Pacific Coast Ranges. Its highest point is approximately 8,848'.