Rancho Muniz (also called "Maniz") was a 17,761-acre (71.88 km2) Mexican land grant in present day Sonoma County, California given in 1845 by Governor Pío Pico to Manuel Torres. The grant extended along the Pacific coast from Salt Point State Park on the north to the Russian River on the south. The grant included Fort Ross.
The Mexican government, which had been concerned about the Russian presence at Fort Ross, was happy to see them leave in 1841, but less pleased when the Russian-American Company sold it to John Sutter. The position of the Mexican government had been that neither land nor improvements had ever belonged to the Russians and hence they could not legally be transferred to anyone else. Within two years after the purchase of Fort Ross, everything Sutter considered salvageable had been removed to his Rancho New Helvetia. In 1843, William (Wilhelm) Benitz, from Baden, Germany, became manager of Sutter's Fort Ross holdings. In 1844 Sutter leased the land to Benitz and a partner, Ernest Rufus, from Württemberg. Both Benitz and Rufus had been in Sutter's militia. That transaction again brought into question the validity of Sutter's title to the property, and Governor Manuel Micheltorena granted Rancho Bodega in part of the southern half of the former Russian claim to Captain Stephen Smith in 1844, and Governor Pio Pico granted the coastal four square league Rancho Muniz in the northern half of the former Russian claim to Manuel Torres in 1845.
Manuel Torres (1826–1910) was born in Lima, Peru, and came to California in 1843 on a merchant ship with his brother-in-law, Captain Stephen Smith. Torres married Mariana (Maryanna) Richardson the daughter of William A. Richardson. Manuel Torres leased Rancho Muniz to Benitz and Rufus, who also owned Rancho German on the Muniz’ northern border, and in 1849, he sold the entire rancho to them. Manuel Torres later operated the Estudillo House in San Leandro, and also the Marin Hotel in San Rafael. Torres was elected to the California State Assembly in 1858-9.