California History At Home: Forming an American State

by Cathie Berglund
Nov. 9, 2026

[Editor’s Note: If you are just joining us for this blog series, please take a few minutes to check out Part 1 and Part 2 for the beginning of the story. Don’t forget to check out the notes on curriculum and suggested geography studies in the “How to Get Started” section of Part 1. We hope that this overview of California history will provide ideas for unit studies, great books to read aloud, and amazing field trips in your corner of the state.]

A New Chapter

Every story worth its salt has conflict, action, and a resolution. The story of California has all of these elements, and many of its defining events took place in your part of the state. So, let’s jump into the next chapter to discover how California became part of America, how the long-sought wealth of its land was finally uncovered, and how both events shaped its future.

California’s story reaches a turning point in the 1840s with the arrival of John C. Frémont, a U.S. Army officer and adventurer who led an 1845 expedition west with 60 scouts, including Kit Carson. His secret instructions were to turn the expedition into a military force if war broke out between the United States and Mexico.

After arriving at Sutter’s Fort in December 1845, Frémont met with Thomas Larkin (introduced in Part 2) and assured local residents of American support if they sought independence from Mexico. Encouraged by this promise, William B. Ide led a group of Californios and Americans to General Mariano Vallejo’s home in Sonoma on June 14, 1846, to negotiate terms for creating an independent California republic. Rather than fight, Vallejo welcomed the group and agreed to remain their captive to avoid bloodshed.

The new nation, known as the California Republic or Bear Flag Republic, lasted only 25 days. On July 9, 1846, U.S. forces raised the American flag over Monterey, and the Bear Flaggers pledged allegiance to the United States.

The Bear Flag Revolt unfolded against the backdrop of a larger conflict. The United States and Mexico were already at war over border disputes and the annexation of Texas, and California soon became another battleground. 

The Mexican-American War ultimately resulted in the United States acquiring about one-third of the land that would eventually make up the 50 states. The war left its mark on California, with several important events worth exploring with your family.

• Battle of San Pasqual (1846) – The War’s bloodiest battle in California

• Treaty of Cahuenga (1847) – Ended the fighting in California

• Treaty of Guadalupe Hidalgo (1848) – Ended the war and ceded vast territories to the United States

Straight to Statehood

As a result of the War, California's population and cities grew with the arrival of settlers and the soldiers that remained to govern the new territory. Local leaders began preparing for statehood, but the U.S. Senate stalled, uncertain how to handle a new territory that threatened the balance between slave and free states.

When James Marshall discovered gold on “Captain” John Sutter’s land on the American River in January 1848, the discovery unleashed the same powerful quest for gold that had once driven Spanish conquistadors. But finding gold was only half the challenge. Getting to California was another matter. 

California's remoteness remained a formidable obstacle, much as it had been for Ulloa during his 1538 search for the mythical island. The journey to California’s gold fields could take more than six months from the East Coast of America, and roughly 1 in 10 gold seekers died along the way or while mining. 

In 1849, travelers had three main routes:

• By sea: From America's East Coast around Cape Horn

• Overland: Along the Old Spanish, California, or Santa Fe Trails

• Via Central America: By ship to Central America, followed by a journey on foot or mule across the Isthmus of Panama. This route took less than half the time but carried serious risks, including accidents, robbery, illness, snakebites, and tropical diseases.

Undaunted, gold seekers poured into California, and its population soared from 10,000 to 235,000 in just three years. The territory rapidly organized a government, ratified a constitution, held elections, and petitioned Congress for statehood—bypassing the usual territorial stage. California entered the Union as the 31st state on September 9, 1850, now celebrated as California Admission Day. 

The Gold Rush brought California into the United States and changed the nation, but it was only the beginning of California’s contributions to America.

The State’s Resourceful Nature

After statehood, California’s story became less dramatic but no less remarkable. Human ingenuity began to overcome the state’s greatest challenge—its geography—while its natural resources and people helped shape the nation over the next 175 years.

Supporting California’s growing population required ambitious new projects and innovations. Here are a few worth exploring:

• Water projects:

• Los Angeles Aqueduct – In 1913, water from the Owens River began traveling 235 miles to the Los Angeles area.

• Hetch Hetchy Reservoir – Brings water from the Tuolumne River in Yosemite to San Francisco.

• St. Francis Dam disaster (1928) – A tragic reminder that controlling nature comes with risks.

• Pony Express – An ambitious mail service that lasted just 18 months!

• First transcontinental telegraph (1861) – Connected California with the rest of the nation.

• Transcontinental Railroad (1869)

Of all these innovations, few impacted California's story as dramatically as the Transcontinental Railroad. When the golden spike joined the Central Pacific and Union Pacific Railroads at Promontory Summit, Utah, California was no longer a faraway, mythical land. Its struggle with isolation was over. Travel from the East Coast now took less than a week, making it easier for families to move west and for goods to reach new markets.

California’s natural resources continue to generate wealth well beyond the Gold Rush. Oil, California's black gold, has contributed billions to the state's economy. Oil was first turned into industry in Los Angeles, where tar seepage was once a nuisance to Native Californians and a trap for animals. Soon the oil industry exploded (literally) in Kern County. 

Beyond oil, California's fertile soil and favorable growing conditions helped make it one of the nation's most important agricultural producers, especially during the Great Depression and after World War II. Today, the state produces more than three-quarters of the nation's fruit and nuts and nearly half its vegetables. (Does your family have a favorite California-grown specialty? Citrus? Almonds? Avocados?)

Yet California's growth and achievements came with challenges and painful chapters. Its history includes important lessons on the resilience of its people after the San Francisco Earthquake of 1906, the internment of Japanese Californians during World War II at Manzanar and Tule Lake, and the Camp Fire in Paradise of 2018.

Ask someone who doesn't call the Golden State home what comes to mind when they think of California, and you might hear the Golden Gate Bridge, the Hollywood sign and movie industry, Disneyland, or Silicon Valley. But over these last few months, we've discovered that there's so much more to explore! We hope this whirlwind tour through the events and achievements that have made California memorable will inspire you and your family to explore the state, uncover its hidden gems, and find your own California treasures.

Suggestions for further study:

• Continue your study of the Gold Rush and find museums or places in your local area where your family can experience panning for gold.

• Read about the tragic story of the Donner Party.

• Dig into the state’s famous trees: Redwoods, Sequoias, Bristlecone Pine, Creosote bush, Torrey Pines, and the Petrified Forest of Sonoma.

• Study the state symbols. (What is the significance of the Greek goddess, Athena, on the state seal?)

• Did you know that California has an (unofficial) state fabric? How is it woven into the state’s history?

• Study the invention of the telegraph and Morse code.

• Visit the La Brea Tarpits (when the renovation is complete). 

• Learn how the Salton Sea was created in 1904.

• California’s aviation industry and the birthplace of the Spirit of St. Louis 

• Geography:

• Create a map of the United States showing each state’s date of admission and order of statehood. Color #31 gold!

• Make a map of California’s earthquake faults.

• Study the differences between geography, topography, and geology.

• Field Trip Reminder – CHEA members have access to the CHEA California Field Trip Guide with over 100 field trip destinations!

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Cathie Berglund is the Exhibits Coordinator for CHEA. She and her husband homeschooled their two, now grown, children through high school. Cathie's homeschooling years sparked a love for the study of God’s Word, for reading and teaching literature, and for encouraging families in their own homeschool journeys.