The South Fork Merced River is the largest

tributary A tributary, or an ''affluent'', is a stream or river that flows into a larger stream (''main stem'' or ''"parent"''), river, or a lake. A tributary does not flow directly into a sea or ocean. Tributaries, and the main stem river into which they ...

of the

Merced River The Merced River (), in the central part of the U.S. state of California, is a -long tributary of the San Joaquin River flowing from the Sierra Nevada (U.S.), Sierra Nevada into the San Joaquin Valley. It is most well known for its swift and st ...

. Most of the river flows within

Yosemite National Park Yosemite National Park ( ) is a List of national parks of the United States, national park of the United States in California. It is bordered on the southeast by Sierra National Forest and on the northwest by Stanislaus National Forest. The p ...

in the

Sierra Nevada The Sierra Nevada ( ) is a mountain range in the Western United States, between the Central Valley of California and the Great Basin. The vast majority of the range lies in the state of California, although the Carson Range spur lies primari ...

California California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...

. The river is long, and its

drainage basin A drainage basin is an area of land in which all flowing surface water converges to a single point, such as a river mouth, or flows into another body of water, such as a lake or ocean. A basin is separated from adjacent basins by a perimeter, ...

covers about , of which are in the national park. The average flow at the mouth is . Originating at about on the south flank of Triple Divide Peak, the South Fork Merced River drains the southwestern slopes of Triple Divide Peak and the west facing slopes of Gale Peak and Sing Peak, then runs southwest through a pine forest flanked by

granite Granite ( ) is a coarse-grained (phanerite, phaneritic) intrusive rock, intrusive igneous rock composed mostly of quartz, alkali feldspar, and plagioclase. It forms from magma with a high content of silica and alkali metal oxides that slowly coo ...

cliffs until the valley walls close in to become a deep canyon as the river turns west. This canyon comes to an end at a large bowl-shaped valley where the river passes the north side of Wawona and receives Chilnualna Creek from the right. After passing under Wawona Road (the south entrance road to the national park) the river drops into another broader, deeper gorge running north, receiving Alder, Rail, Big, and Bishop Creeks, all from the right. Soon the river turns west, crossing the boundary of Yosemite National Park and the

Sierra National Forest Sierra National Forest is a U.S. national forest located on the western slope of the central Sierra Nevada in California, bounded on the northwest by Yosemite National Park and on the south by Kings Canyon National Park. The forest is known for ...

and entering the

foothills Foothills or piedmont are geography, geographically defined as gradual increases in elevation at the base of a mountain range, higher hill range or an highland, upland area. They are a transition zone between plains and low terrain, relief hill ...

of the Sierra Nevada, and merges with the Merced River some downstream of the end of

Yosemite Valley Yosemite Valley ( ; ''Yosemite'', Miwok for "killer") is a U-shaped valley, glacial valley in Yosemite National Park in the western Sierra Nevada (U.S.), Sierra Nevada mountains of Central California, United States. The valley is about long a ...

. The river was mislabelled "Illilouette Creek" on 1871 California Geological Survey reports. Illilouette Creek is actually another tributary of the Merced River further to the east.

References

{{Central Valley Rivers * Rivers of Mariposa County, California Rivers of the Sierra Nevada (United States) Rivers of Yosemite National Park Sierra National Forest Rivers of Northern California Rivers of the Sierra Nevada in California Wild and Scenic Rivers of the United States