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San Luis Rey Watershed

The San Luis Rey Watershed is located in the northwestern corner of San Diego County, encompassing approximately 562 square miles. The San Luis Rey River, which flows east to west, stretches over 55 miles from its headwaters in the Palomar and Hot Springs Mountains before discharging in the Pacific Ocean near the City of Oceanside’s Harbor.  Land ownership in the San Luis Rey Watershed is three-fold, with almost half (49%) being privately owned, 37% being publicly owned, and approximately 14% encompassing six federally recognized Tribal Indian Reservations.


More than half of the land (54%) in the San Luis Rey Watershed is undeveloped. Residential use, which compromises approximately 15% of the watershed‘s land use, can be seen in cities such as Oceanside and the unincorporated areas of Fallbrook, Bonsall, and Valley Center.  Agricultural use accounts for about 14% of the total land use in the watershed, which includes cattle grazing as well as the production of a wide variety of agricultural crops, such as avocados, citrus and ornamental nursery stock.