El Capitan County Preserve in Lakeside protects 2,619 acres of granite ridgeline, coastal sage scrub, and mixed chaparral along Blue Sky Ranch Road, offering one of San Diego County's most demanding hiking experiences. The preserve shares Wildcat Canyon Road access with Oakoasis County Preserve, forming a continuous habitat corridor through oak woodland and riparian zones that support golden eagle nesting territories and the endemic Lakeside ceanothus. El Cajon Mountain's summit trail gains over 3,200 feet of elevation across a 10.6-mile out-and-back route that typically requires six to seven hours to complete, with light rock scrambling required near the peak. The preserve closes each August due to extreme summer heat but otherwise provides year-round access to a viewpoint unique in the San Diego County park system — a single overlook revealing three reservoirs simultaneously, including El Capitan Reservoir. The trailhead staging area off Blue Sky Ranch Road channels hikers through the Mapleview and Ashwood corridors, where Lakeside's commercial core — anchored by Cafe 67 — provides the nearest dining and provisions before the 3,200-foot climb begins. A 2024 Board of Supervisors action added 75 donated acres connecting the preserve to the Historic Flume Corridor and El Monte County Park, expanding the countywide MSCP preserve network to nearly 46,300 total acres.