The following timeline traces the territorial evolution of California, the thirty-first state admitted to the United States of America, including the process of removing Indigenous Peoples from their native lands, or restricting them to reservations.
Rio de Buen Guia (Colorado River) claim made by Hernando de Alarcon on behalf of Spain, September 1540 Rio de Tizon Delta (Imperial Valley) claim made by Melchor Diaz on behalf of Spain, December 1540. San Miguel (San Diego) claim made by Juan Rodríguez Cabrillo on behalf of Spain, 1542
New Albion ( Point Reyes) claim made by Sir Francis Drake on behalf of England, 1579 Rio Colorado (Colorado River) claim made by Juan de Onate on behalf of Spain, January 1605 Rio Colorado (Yuma Crossing) claim made by Eusebio Kino on behalf of Spain, 1701
Las Californias claimed by Spain under the governance of the Viceroyalty of New Spain, 1768–1804
Northern California coast claimed by Ivan Kuskov on behalf of Russia, 1812 [1] 
Monterey, California held by Hippolyte Bouchard on behalf of Argentina (6 days), 1818 [2] 
Army of the Three Guarantees, 1821
First Mexican Empire, 1821–1823
First Mexican Republic, 1824–1835 
California's Lone Star coup and declaration of independence, 1836
California Republic (25 days), 1846
Alta California administered by the United States as part of the Mexican Cession Unorganized territory, 1848–1850 
California Statehood Act, September 9, 1850 [3] CONSTITUTION OF THE STATE OF CALIFORNIA (1849)
Article XII; Boundary
The Boundary of the State of California shall be as follows:
Commencing at this point of intersection of 42d degree of north latitude with the 120th degree of longitude west from Greenwich, and running south on the line of said 120th degree of west longitude until it intersects the 39th degree of north latitude; thence running in a straight line in a south easterly direction to the River Colorado, at a point where it intersects the 35th degree of north latitude; thence down the middle of the channel of said river, to the boundary line between the United States and Mexico, as established by the Treaty of May 30th, 1848; thence running west and along said boundary line to the Pacific Ocean, and extending therein three English miles; thence running in a northwesterly direction, and following the direction of the Pacific Coast to the 42d degree of north latitude, thence on the line of said 42d degree of north latitude to the place of beginning. Also all the islands, harbors, and bays, along adjacent to the Pacific Coast.
Territorial evolution of Arizona 
Territorial evolution of Nevada 
Territorial evolution of Oregon 
Alta California, also known as Nueva California among other names, was a province of New Spain formally established in 1804. Along with the Baja California peninsula, it had previously comprised the province of Las Californias, but was made a separate province in 1804. Following the Mexican War of Independence, it became a territory of Mexico in April 1822 and was renamed Alta California in 1824.
Human history in California began when indigenous Americans first arrived some 13,000 years ago. Coastal exploration by the Spanish began in the 16th century, with further European settlement along the coast and in the inland valleys following in the 18th century. California was part of New Spain until that kingdom dissolved in 1821, becoming part of Mexico until the Mexican–American War (1846–1848), when it was ceded to the United States under the terms of the 1848 Treaty of Guadalupe Hidalgo. The same year, the California gold rush began, triggering intensified U.S. westward expansion. California joined the Union as a free state via the Compromise of 1850. By the end of the 19th century, California was still largely rural and agricultural, with a population of about 1.4 million.
The Treaty of Guadalupe Hidalgo officially ended the Mexican–American War (1846–1848). It was signed on 2 February 1848 in the town of Guadalupe Hidalgo.
The Adams–Onís Treaty of 1819, also known as the Transcontinental Treaty, the Spanish Cession, the Florida Purchase Treaty, or the Florida Treaty, was a treaty between the United States and Spain in 1819 that ceded Florida to the U.S. and defined the boundary between the U.S. and Mexico. It settled a standing border dispute between the two countries and was considered a triumph of American diplomacy. It came during the successful Spanish American wars of independence against Spain.
The Territory of New Mexico was an organized incorporated territory of the United States from September 9, 1850, until January 6, 1912. It was created from the U.S. provisional government of New Mexico, as a result of Nuevo México becoming part of the American frontier after the Treaty of Guadalupe Hidalgo. It existed with varying boundaries until the territory was admitted to the Union as the U.S. state of New Mexico in 1912. This jurisdiction was an organized, incorporated territory of the US for nearly 62 years, the longest period of any territory in the contiguous United States.
The Mexican Cession is the region in the modern-day Western United States that Mexico previously controlled, then ceded to the United States in the Treaty of Guadalupe Hidalgo in 1848 after the Mexican–American War. This region had not been part of the areas east of the Rio Grande that had been claimed by the Republic of Texas, which had been claiming independence since its Texas Revolution of 1836 and subsequent brief war for independence, followed afterwards a decade later by the American annexation and admitted statehood in 1845. It had not specified the southern and western boundary of the new state of Texas with New Mexico consisting of roughly 529,000 square miles (1,370,000 km2), not including any Texas lands, the Mexican Cession was the third-largest acquisition of territory in U.S. history, surpassed only by the 827,000-square-mile (2,140,000 km2) Louisiana Purchase of 1803 and the later 586,000-square-mile (1,520,000 km2) Alaska Purchase from Russia in 1867.
The history of California can be divided into the Native American period, the European exploration period (1542–1769), the Spanish colonial period (1769–1821), the Mexican period (1821–1848), and United States statehood. California was one of the most culturally and linguistically diverse areas in pre-Columbian North America. After contact with Spanish explorers, many of the Native Americans died from foreign diseases. Finally, in the 19th century there was a genocide by United States government and private citizens, which is known as the California genocide.
The Californias, occasionally known as the Three Californias or the Two Californias, are a region of North America spanning the United States and Mexico, consisting of the U.S. state of California and the Mexican states of Baja California and Baja California Sur. Historically, the term Californias was used to define the vast northwestern region of Spanish America, as the Province of the Californias, and later as a collective term for Alta California and the Baja California peninsula.
In Alta California and Baja California, ranchos were concessions and land grants made by the Spanish and Mexican governments from 1775 to 1846. The Spanish Concessions of land were made to retired soldiers as an inducement for them to settle in the frontier. These Concessions reverted to the Spanish crown upon the death of the recipient.
The history of Hispanics and Latinos in the United States is wide-ranging, spanning more than four hundred years of American colonial and post-colonial history. Hispanics became the first American citizens in the newly acquired Southwest territory after the Mexican–American War, and remained a majority in several states until the 20th century.
Yerba Buena was the original name of the settlement that later became San Francisco. Located near the northeastern end of the San Francisco Peninsula, between the Presidio of San Francisco and the Mission San Francisco de Asís, it was originally intended as a trading post for ships visiting San Francisco Bay. The settlement was arranged in the Spanish style around a plaza that remains as the present day Portsmouth Square.
The area currently occupied by the U.S. State of New Mexico has undergone numerous changes in occupancy and territorial claims and designations. This geographic chronology traces the territorial evolution of New Mexico.
The following outline traces the territorial evolution of the U.S. State of Wyoming.
The following outline traces the territorial evolution of the U.S. state of Oregon.
The following timeline traces the territorial evolution of the U.S. State of Utah.
The following timeline traces the territorial evolution of the U.S. State of Arizona.
The following outline traces the territorial evolution of the U.S. State of Nevada.
Baja California Territory was a Mexican territory from 1824 to 1853, and 1854 to 1931, that encompassed the Baja California peninsula of present-day northwestern Mexico. It replaced the Baja California Province (1773–1824) of the Spanish colonial Viceroyalty of New Spain, after Mexican independence. Along with Alta California, the two territories were split from the Spanish Californias region.
Rancho Las Camaritas was an Alta California land grant, a square of 300 Mexican varas on each side; varas being one pace, in this case 2.75 feet to José de Jesús Noé on January 21, 1840, by Governor Juan Bautista Alvarado. Millions of acres of California land was given at no charge to men between 1784 and 1846 by the Spanish (1784–1810) or Mexican governments (1819–1846) mostly for military service to raise cattle on. About 300 of the 800 Land grants were sizable varying from a few thousand to 1.5 million acres – see List of ranchos of California for the larger grants. Following the Mexican–American War, the land grants were challenged with most of them falling into American hands. Only one land grant has remained undeveloped. The ownership of Las Camaritas was disputed in court by the U.S. government from 1856 until 1882 due to conflicting documentation presented by its American owner Ferdinand Vassault after a string of sales initiated by Jose Noe sometime between 1842 and 1846.
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