Teodosio Juan Yorba (1805–1863), the son of
Jose Antonio Yorba grantee of
Rancho Santiago de Santa Ana, was granted the eleven square league
Rancho Arroyo Seco in 1840, and the four square league Rancho Lomas de Santiago in 1846. With the
cession of California to the United States following the
Mexican–American War, the 1848
Treaty of Guadalupe Hidalgo provided that the land grants would be honored. As required by the Land Act of 1851, a claim for Rancho Lomas de Santiago was filed with the
Public Land Commission in 1852, and the grant was
patented to Teodosio Yorba in 1868. Teodosio sold the rancho to
William Wolfskill in 1860. Joseph E. Pleasants took charge of Wolfskill's new cattle operations. Already overgrazed, and largely unfarmable due to its steep, hilly terrain, the Santa Ana range could not sustain the large cattle herds. In 1866, Benjamin and Thomas Flint,
Llewellyn Bixby and
James Irvine acquired the rancho, and it eventually became part of the
Irvine Ranch. ==Historic sites of the Rancho==