at the Aliso Creek headwaters, but it is uncertain where the boundary was that divided Santiago Creek within the native territories. Archaeological evidence suggests that the upper portions of the creek were settled by Native Americans, and some historical accounts including those of the Spanish settlers, mention the Acjachemen lived in the canyon of upper Santiago Creek. These first inhabitants of the Santiago Creek Canyon lived in semi-permanent villages close to running water. The upper canyon was in the Acjachemen homelands, while the lower (northwestern) part of the watershed, likely downstream of present-day Irvine Lake, was in the Tongva homelands. The Native Americans had been drawn to the area by the abundant riparian zone found along Santiago Creek and some of its perennial tributaries. They subsisted on a diet of primarily acorns, using the ground acorn powder to form a type of porridge known as atole. They ground the acorns in stone mortars carved into large boulders and rock formations, with some remaining in the creek's canyon areas. Spanish colonization In 1769 the Spanish Portolá expedition, first European land exploration of Alta California, traveled northwest along the southern edge of the Santa Ana Mountains. They camped near where Santiago Creek emerges from the mountains on July 27, and near the Santa Ana River on July 28. Padre Juan Crespi noted in his diary that the creek was named for the Apostle Santiago el Mayor". Later Spaniards named the creek's canyon Cañada de Madera (timber canyon). The mountain whose southwestern flank is the creek's headwaters, known as Kalawpa by the indigenous peoples, was renamed Santiago Peak, after the creek. The Spanish left accounts mentioning the Juaneño, the name given to the Acjachemen by the Spanish missionaries after the founding of Mission San Juan Capistrano, located to the southeast at the confluence of San Juan and Trabuco Creeks. One of the first settlers in the Santiago Creek watershed was Jose Pablo Grijalva, a former Spanish soldier, who arrived in 1784. He and his son-in-law, José Antonio Yorba, began grazing cattle in Santiago Creek Canyon in the 1790s. He built an adobe house beside Santiago Creek in 1796. Later settlers included the Peraltas and Sepúlvedas. Ranchos Three adjoining ranchos were granted within the creek's drainage. The Spanish era Rancho Santiago de Santa Ana (1810), extending from the Santa Ana River to the Santa Ana Mountains, was -long, . The later Mexican era land