Walnut Creek (Contra Costa County)

Walnut Creek Arroyo de Las Nueces,[1] Arroyo de Los Nogales[1]
Secondary beaver dam on lower Walnut Creek provides happy hunting perch for a great egret. Courtesy Cheryl Reynolds, Worth a Dam, 2013
Location of the mouth of Walnut Creek in California
Location
Country	United States
State	California
Region	Contra Costa County
Cities	Walnut Creek, Pleasant Hill, Four Corners, Concord, Pacheco, Vine Hill, Mococo, Martinez
Physical characteristics
Source	Confluence of Las Trampas Creek and Tice Creek
• location	Walnut Creek, California 375338N 1220335W
• coordinates	37°53′38″N 122°3′35″W / 37.89389°N 122.05972°W / 37.89389; -122.05972[2]
• elevation	144 ft (44 m)
Mouth	Suisun Bay
• location	Martinez, California
• coordinates	38°1′27″N 122°4′13″W / 38.02417°N 122.07028°W / 38.02417; -122.07028[2]
• elevation	2 ft (0.61 m)
Basin size	146 sq mi (380 km2)

The Walnut Creek mainstem is a 12.3-mile-long (19.8-kilometer)^[3] northward-flowing stream in northern California. The Walnut Creek watershed lies in central Contra Costa County, California and drains the west side of Mount Diablo and the east side of the East Bay Hills.^[4] The Walnut Creek mainstem is now mostly a concrete or earthen flood control channel until it reaches Pacheco Creek^[5] on its way to Suisun Bay. Walnut Creek was named for the abundant native Northern California walnut trees (Juglans hindsii) which lined its banks historically. The city of Walnut Creek, California was named for the creek when its post office was established in the 1860s.^[1]