[1] This species now occurs most commonly along the northern and southern Coast Ranges, and in isolated areas in the foothills of the Sierra Nevada mountains.

[10] The back is a brown, grey, olive, or reddish color, with black flecks and dark, irregular, light-centered blotches, and is coarsely granular.

A dark mask with a whitish border occurs above the upper jaw, and black and red or yellow mottling is in the groin.

[10] The juvenile frog has more pronounced dorsal spotting, and may have yellow, instead of red, markings on the undersides of the hind legs.

There have been instances where the species was viewed preying on juvenile snakes, small mammals such as mice, and other frogs and tadpoles.

[10] The species inhabits dense, shrubby, or emergent riparian vegetation and still or slow-moving perennial and ephemeral water bodies that also serve as breeding sites.

They either stay immobile, quickly leap into vegetation in an upland habitat or a water source nearby, or, rarely, give off an alarm call to indicate danger.

One cause of the population decline is habitat loss and destruction, but introduced predatory species, such as American bullfrogs, might also be a factor.

Their habitats are in close proximity to roads and trails, indicating traffic, runoff, pollution, and other human interference may be a significant threat to the species.

On September 17, 2008, the US Fish and Wildlife Service proposed to more than triple the habitat of the California red-legged frog, citing political manipulation by former Deputy Assistant Secretary Julie MacDonald at the United States Department of the Interior.