Rancho Cosumnes was a 26605 acres (107.7 km²) Mexican land grant

Ranchos of California

The Spanish, and later the Méxican government encouraged settlement of territory now known as California by the establishment of large land grants called ranchos, from which the English ranch is derived. Devoted to raising cattle and sheep, the owners of the ranchos attempted to pattern themselves...

 in present day Sacramento County, California

Sacramento County, California

Sacramento County is a county in the U.S. state of California. Its county seat is Sacramento, which is also the state capital. As of 2010 the county had a population of 1,418,788....

 given in 1844 by Governor Manuel Micheltorena

Manuel Micheltorena

Manuel Micheltorena was a Brigadier General of the Mexican Army, Adjutant-General of the same, Governor, Commandant-General and Inspector of the Department of the California...

 to William Edward Petty Hartnell

William Edward Petty Hartnell

William Edward Petty Hartnell, a.k.a. Don Guillermo Arnel was a prominent early immigrant to Alta California who played a vital role in the history of Monterey County, California as well as the history of California.-Early life:William Hartnell was born in Backbarrow, Lancashire, England, and...

. The grant extended along the south bank of the Cosumnes River

Cosumnes River

The Cosumnes River is a river in northern California in the United States. It rises on the western slope of the Sierra Nevada and flows approximately into the Central Valley, emptying into the Mokelumne River in the Sacramento-San Joaquin Delta.-Name:...

, across from Rancho Omochumnes

Rancho Omochumnes

Rancho Omochumnes was a Mexican land grant in present day Sacramento County, California given in 1844 by Governor Manuel Micheltorena to Jared Dixon Sheldon...

.

History

William Edward (Guillermo Eduardo) Petty Hartnell (1798–1854) received the five square league Rancho Todos Santos y San Antonio

Rancho Todos Santos y San Antonio

Rancho Todos Santos y San Antonio was a Mexican land grant in present day Santa Barbara County, California given in 1841 by Governor Juan B. Alvarado to William Edward Petty Hartnell. The grant extended along San Antonio Creek and encompassed present day Orcutt., northwest of Lompoc-History:W....

 in Santa Barbara County

Santa Barbara County, California

Santa Barbara County is a county located in the southern portion of the U.S. state of California, on the Pacific coast. As of 2010 the county had a population of 423,895. The county seat is Santa Barbara and the largest city is Santa Maria.-History:...

 from Governor Juan B. Alvarado in 1841 and sold his Rancho El Alisal

Rancho El Alisal

Rancho El Alisal was a Mexican land grant in present day Monterey County, California given in 1833 by Governor José Figueroa to brothers Feliciano and Mariano Soberanes and to William Edward Petty Hartnell. Alisal means Alder tree in spanish...

 to Alvarado. In 1844, Hartnell was granted the eleven square league Rancho Cosumnes from Micheltorena.

With the cession

Mexican Cession

The Mexican Cession of 1848 is a historical name in the United States for the region of the present day southwestern United States that Mexico ceded to the U.S...

 of California to the United States following the Mexican-American War, the 1848 Treaty of Guadalupe Hidalgo

Treaty of Guadalupe Hidalgo

The Treaty of Guadalupe Hidalgo is the peace treaty, largely dictated by the United States to the interim government of a militarily occupied Mexico City, that ended the Mexican-American War on February 2, 1848...

 provided that the land grants would be honored. As required by the Land Act of 1851, a claim for Rancho Cosumnes was filed with the Public Land Commission

Public Land Commission

The Public Land Commission, a former agency of the United States government, was created following the admission of California as a state in 1850 . The Commission's purpose was to determine the validity of prior Spanish and Mexican land grants in California.California Senator William M...

 in 1852. Hartnell claimed eleven square leagues for Rancho Cosumnes, but because he had another claim for the five square league Rancho Todos Santos y San Antonio, the Land Commission Rancho Cosumnes was reduced to six square leagues - so that the total would not have exceeded the eleven square league maximum under Mexican law. The U.S. Supreme Court affirmed the decree, and the grant was patented

Land patent

A land patent is a land grant made patent by the sovereign lord over the land in question. To make a such a grant “patent”, such a sovereign lord must document the land grant, securely sign and seal the document and openly publish the same to the public for all to see...

 to William Edward Petty Hartnell in 1869.

When Hartnell died in 1854, his widow, Maria Teresa de la Guerra de Hartnell and the 11 children inherited the rancho. Hartnell wrote in his will - "My principal object is to prevent any member of the law from having anything whatsover to do with my property or with my executors or heirs." Maria Teresa de la Guerra’s brother, Pablo de la Guerra

Pablo de la Guerra

Pablo de la Guerra , from the de la Guerra family of Santa Barbara, California, was the Acting Lieutenant Governor of California, 1861-1862...

was administrator of the estate.