Little Rock Creek is a 16.7-mile (26.9 km) northwestward-flowing stream in the San Gabriel Mountains and Mojave Desert, within northern Los Angeles County, California.

[1] The California Office of Environmental Health Hazard Assessment has issued a safe eating advisory for any fish caught in Little Rock Reservoir due to elevated levels of mercury and PCBs.

At this wet spot, where the San Andreas Fault system forced water to the surface, the Garcia cienaga (canyon) was located.

[6] Little Rock Creek's originates just west of the summit of 8,199 feet (2,499 m) Mount Williamson and flows down the north slope of the San Gabriel Mountains.

[11] The upper segment of the creek is located in the newly designated Pleasant View Ridge Wilderness area and supports an important population of endangered mountain yellow-legged frog (Rana muscosa).