A creek that starts in San Dimas and meets the San Gabriel River near the cities of El Monte and Baldwin Park.
Walnut Creek should start somewhere in the numerous headwaters in the San Dimas Experimental Forest of the Angeles Natioal Forest, but due to nearly 100 years of flood control it appears to start next to Puddingstone Reservoir, which is, interestingly supposed to be filled with Walnut Creek water. A little west of the reservoir is Walnut Creek Park, an equestrian and hiking trail. It is a startly contrast to most of the creek since it is left in a relatively natural (Although most likely man-made) condition, it abruptly ends shortly before reaching Covina Hills Rd. To get to it find the small dirt parking lot located near the underpass of Interstate 210. In West Covina there is also a seemingly abandoned bike trail (There is literally 2 inches of dirt covering the asphalt in some parts) along the concrete channel. It ends abruptly at a gate.