Contra Costa County, California
Contra Costa County is a county located in the U.S. state of California, in the East Bay of the San Francisco Bay Area. As of the 2020 United States census, the population was 1,165,927. The county seat is Martinez. It occupies the northern portion of the East Bay region of the San Francisco Bay Area and is primarily suburban. The county's name refers to its position on the other side of the bay from San Francisco. Contra Costa County is included in the San Francisco–Oakland–Berkeley, CA Metropolitan Statistical Area.
History
Pre-human
In prehistoric times, particularly the Miocene epoch, portions of the landforms now in the area were populated by a wide range of now extinct mammals, known in modern times by the fossil remains excavated in the southern part of the county. In the northern part of the county, significant coal and sand deposits were formed in even earlier geologic eras. Other areas of the county have ridges exposing ancient but intact seashells, embedded in sandstone layers alternating with limestone. Layers of volcanic ash ejected from geologically recent but now extinct volcanoes, compacted and now tilted by compressive forces, may be seen at the site of some road excavations. This county is an agglomeration of several distinct geologic terranes, as is most of the greater San Francisco Bay Area, which is one of the most geologically complex regions in the world. The great local mountain Mount Diablo has been formed and continues to be elevated by compressive forces resulting from the action of plate tectonics and at its upper reaches presents ancient seabed rocks scraped from distant oceanic sedimentation locations and accumulated and lifted by these great forces. Younger deposits at middle altitudes include pillow lavas, the product of undersea volcanic eruptions.Native American period
The Bay Miwok, Yokut and Ohlone people lived in the area now known as Contra Costa County before the arrival of Spanish colonists. The Volvon triblet of the Miwok lived on Tuyshtak until they were forcibly moved from their land into the Spanish missions in the early 1800s.The Saklan tribe lived between Moraga, along San Leandro Creek, to Lafayette. Beginning in 1772, expeditions of Spanish missionaries and soldiers from Mission San José entered the San Ramon Valley. Early contact was fleeting and mostly peaceful, however, in the late 1700s, Spanish cattle were grazed the territory of the Saklan and their neighbors. The Saklans were one of the few groups who mounted resistance against the efforts of the Spanish to convert them to Christianity. Christian natives were sent to the Saklans to convince them to give up their culture and come to Mission San Jose; they were killed by the Saklans who wanted nothing to do with the Spanish way of life. A punitive expedition was sent to the area in 1797 to repress the Saklans, and a battle was fought in modern-day Lafayette. In the early 1800s, many Saklan fled to the mission as a result of societal collapse from disease. By the 1810s the Saklan's tribal range was essentially devoid of inhabitants.
Spanish colonial
Early interaction of these Native Americans with Europeans came with the Spanish colonization via the establishment of missions in this area, with the missions in San Jose, Sonoma, and San Francisco and particularly the establishment of a Presidio in 1776. Although there were no missions established within this county, Spanish influence here was direct and extensive, through the establishment of land grants from the King of Spain to favored settlers.Mexican land grants
In 1821 Mexico gained independence from Spain. While little changed in ranchero life, the Mexican War of Independence resulted in the secularization of the missions with the re-distribution of their lands, and a new system of land grants under the Mexican Federal Law of 1824. Mission lands extended throughout the Bay Area, including portions of Contra Costa County. Between 1836 and 1846, during the era when California was a province of independent Mexico, the following 15 land grants were made in Contra Costa County.The smallest unit was one square league, or about seven square miles, or, maximum to one individual was eleven leagues, or, including no more than of irrigable land. Rough surveying was based on a map, or diseño, measured by streams, shorelines, and/or horseman who marked it with rope and stakes. Lands outside rancho grants were designated el sobrante, as in surplus or excess, and considered common lands. The law required the construction of a house within a year. Fences were not required and were forbidden where they might interfere with roads or trails. Locally a large family required roughly 2000 head of cattle and two square leagues of land to live comfortably. Foreign entrepreneurs came to the area to provide goods that Mexico could not, and trading ships were taxed.
- Rancho Cañada de los Vaqueros was granted to Francisco Alviso, Antonio Higuera, and Manuel Miranda.
- Two ranchos, both called Rancho San Ramon, were granted by the Mexican government in the San Ramon Valley. In 1833, Bartolomé Pacheco and Mariano Castro shared the two square league Rancho San Ramon. José María Amador was granted a four square league Rancho San Ramon in 1834.
- In 1834 Rancho Monte del Diablo was confirmed with to Salvio Pacheco. The Pacheco family settled at the Rancho in 1846. The boundary lines were designated with stone markers. Clayton was later located on El Sobrante's lands just east of Rancho Monte del Diablo.
- In 1834, Rancho Arroyo de Las Nueces y Bolbones, aka Rancho San Miguel, was granted to Juana Sanchez de Pacheco, in recognition of the service of Corporal Miguel Pacheco 37 years earlier ; the grant was for two leagues, but drawn free hand on the diseño/map, and reading "two leagues, more or less" as indicated in the diseño, but actually including and confirmed for nearly four leagues or nearly, but only were ever shown as having once belonged to Juana Sanchez.
- 'Meganos' means 'sand dunes.' A "paraje que llaman los Méganos" 'place called the sand dunes' is mentioned in Durán's diary on May 24, 1817. Two Los Meganos Ranchos were granted, later differentiated as Rancho Los Meganos in what is now the Brentwood area, to Jose Noriega then acquired by John Marsh; and Rancho Los Medanos.
Bear Flag Republic and statehood
The exclusive land ownership in California by Hispanics in California would soon end. John Marsh, owner of Rancho Los Meganos in Contra Costa County, sent letters to influential people in the eastern United States extolling the climate, soil, and potential for agriculture in California, with the purpose of encouraging Americans to immigrate to California and lead to its becoming part of the United States. His letters were published in newspapers throughout the East which started the first wagon trains to California. He invited the settlers to stay on his ranch, and Rancho Los Meganos became the terminus of the California trail.This led to the Bear Flag Revolt in 1846 when about 30 settlers originally from the United States declared a republic in June 1846 and were enlisted and fighting under the U.S. flag by July 1846. Following the Mexican–American War of 1846–48, California was controlled by U.S. settlers organized under the California Battalion and the U.S. Navy's Pacific Squadron. After some minor skirmishes, California was under U.S. control by January 1847 and formally annexed and paid for by the U.S. in 1848. By 1850, California's population of over 100,000 was rapidly growing due to the gold rush and the large amount of gold being exported east, which gave California enough clout to choose its own boundaries, write its own constitution, and be admitted to the Union as a free state in 1850 without going through territorial status as required for most other states.
In 1850 California had a non-Indian population of over 100,000. The number of Indians living in California in 1850 has been estimated to be from 60,000 to 100,000. By 1850 the Mission Indian populations had largely succumbed to disease and abuse and only numbered a few thousand. California's 1852 state Census gives 31,266 Indian residents, but this is an under-count since there was little incentive and much difficulty in getting it more correct.
County creation
Contra Costa County was one of the original 27 counties of California, created in 1850 at the time of statehood. The county was originally to be called Mt. Diablo County, but the name was changed prior to incorporation as a county. The county's Spanish language name means opposite coast, because of its location opposite San Francisco, in an easterly direction, on San Francisco Bay. Southern portions of the county's territory, including all of the bayside portions opposite San Francisco and northern portions of Santa Clara County, were given up to form Alameda County effective March 25, 1853.The land titles in Contra Costa County may be traced to multiple subdivisions of a few original land grants. The grantee's family names live on in a few city and town names such as Martinez, Pacheco and Moraga and in the names of streets, residential subdivisions, and business parks. A few mansions from the more prosperous farms have been preserved as museums and cultural centers and one of the more rustic examples has been preserved as a working demonstration ranch, .
In the 1860 United States Census, Contra Costa County had a population of 4,381.