At in size, the watershed of Salt Creek is the smallest major watershed in the county. Shaped roughly like a Y, the two arms of the mostly residential watershed represent the drainage basins of Salt Creek and its major tributary, the Arroyo Salada Storm Channel. Bounded almost entirely by the San Joaquin Hills, the watershed consists of a hilly region east of the Aliso Creek watershed, south of the Sulphur Creek drainage basin, and west of the valley of San Juan Creek and Trabuco Creek. The easternmost part of the watershed lies within San Juan Capistrano, and the southernmost part between Dana Point and Laguna Beach. Two-thirds of the watershed lies within the city of Laguna Niguel.