The Bear Flag Revolt began on June 14, 1846 when California was declared a Republic. The California Republic lasted less than one month and ended on July 9, 1846 due to the California Annexation by the United States. The Bear Flag was the original emblem of the California Republic and flown during the Bear Flag Revolt which preceded the U.S. acquisition of California when Mexico ceded the land to the United States under the terms of the 1848 Treaty of Guadalupe Hidalgo.

California Republic for kids: The Bear Flag Revolt Flag
The Bear Flag Revolt in California was given this name because the American settlers (subsequently called the 'Bear Flaggers') created a flag showing a grizzly bear next to the red star which is a .symbol of the California "Lone Star Republic".

Bear Flag Revolt Flag
The Bear Flag Revolt flag was designed and made by William L. Todd, who was the cousin of Mary Todd Lincoln, the wife of the future American president, Abraham Lincoln. The bear was an ancient heraldic symbol that symbolized strength and bravery. The bear is also the emblem of ferocity in the protection of family and countrymen. The grizzly bear is still featured on  the modern state Flag of California.

California Republic for kids: The 1836 Revolt
Alta California, meaning Upper California, was originally a province and territory in the Viceroyalty of New Spain which later became a territory in independent Mexico. The Spanish colony of California was divided into Alta ("Upper") and Baja ("Lower") California. he first revolt against Mexican rule occured in 1836 and was led by Juan Alvarado and Isaac Graham. During the first rebellion the American rebels captured Monterey and declared California "a free and sovereign state". Their first revolt failed to secure independence for the California Republic but it inspired the design of the flag used in the Bear Flag Revolt that followed 10 years later in 1846.

California Republic and the Bear Flag Revolt for kids: The Seizure of California
The Bear Flag Revolt and the California Republic led to the seizure of California by the United States. There were now many American settlers in California, especially at Monterey. The flag adopted to represent the California Republic had a figure of a grizzly bear painted on it, and the California republic became known as the Bear Republic. Commodore Stockton with a small fleet was on the Pacific coast and John C. Fremont assisted the Bear Republicans until soldiers under Colonel Kearney reached them from the United States via Santa Fe. The informal Treaty of Cahuenga on January 13, 1848 ended the fighting of the Mexican-American War in Alta California and Mexico formally ceded Alta California and other territories to the United States under the terms of the Treaty of Guadalupe Hidalgo in 1848

Bear Flag Revolt and the California Republic Timeline and Facts for kids
The Bear Flag Revolt and the California Republic Facts and Timeline for kids is detailed below. The history of the Bear Flag Revolt and the California Republic is told in a factual timeline sequence consisting of a series of short facts providing a simple method of relating the famous people and events surrounding the Bear Flag Revolt and the California Republic. 

1821: The Mexicans won their independence from Spain and founded the Mexican Republic. Immigrants from the US settled in Alta California

April 6, 1830: The Mexican government bans US immigration

October 2, 1835: The Texas Revolution began with the battle of Gonzales against the Mexican forces under Santa Anna and on March 2, 1835 Texas declares independence from Mexico

January 1836: Nicolas Gutierrez was appointed as interim governor in January 1836 but was very unpopular.

November 1836: Juan Alvarado and a group of Americans led by Isaac Graham, staged a revolt in November 1836 and forced Gutierrez to relinquish power.

1836: Juan Alvarado and Isaac Graham capture Monterey and declared California "a free and sovereign state

Juan Alvarado was made twice Governor of Alta California from 1836 to 1837, and 1838 to 1842

The Americans wanted independence for California but Juan Alvarado preferred staying a part of Mexico, but with greater autonomy that was given following the revolt.

March 3, 1837: United States recognizes the Republic of Texas which fuels the aspirations of the Californians to establish the California Republic

April 1840: A report of a planned revolt against Alvarado by a group of about 100 American settlers, led by his former ally Isaac Graham, caused their arrest and deportation to Mexico City for trial.

Their arrest led to a diplomatic crisis, involving Mexico and the United States  that became known as the "Graham Affair".

June 1841: Isaac Graham and his rebels were acquitted of all charges

July 1841: A recommendation was made by Alvarado that Mexico should send military reinforcements to enforce their control of California

January 1842: Mexican Santa Anna sends Brigadier General Manuel Micheltorena and 300 men to California

October 19, 1842: US Commodore Thomas ap Catesby Jones mistakenly believes that war had broken out between the United States and Mexico and sails into Monterey Bay demanding the surrender of the fort increasing tensions with Mexico still further

November 14, 1844: Manuel Castro leads a group of Californios in a revolt Mexican authority

February 1845: The rebels won the Battle of Providencia and Micheltorena and his Mexican troops leave California

March 4, 1845: James Polk becomes US President. His goal is American territorial expansion to the Pacific coast

1845: John O’Sullivan initiates the phrase 'Manifest Destiny'

1845: President James Polk offers to purchase California but the Mexican government refuses to sell the land at any price

November 1845: Captain John C. Fremont, a U.S. Army officer arrives on an exploratory expedition and encourages American settlers in North California to launch a revolt against Mexican rule

May 13, 1846: The United States declares war with Mexico and the Mexican American War begins, although this is not known in Alta California until July 1846

June 14, 1846: Learning of a report that the Mexican government was threatening to expel all settlers who were not Mexican citizens 36 northern rebels seize the Mexican garrison at Sonoma, capture Mariano Guadalupe Vallejo, the Mexican Commandante of Northern California and the Bear Flag Revolt begins

June 14, 1846: William B. Ide is made the first, and only, President of the California Republic (whose administration would last for 25 days)

June 15, 1846: William B. Ide releases a proclamation that the Mexican province was now the California Republic

June 17, 1846:  The rebels raise a homemade flag, designed by  William L. Todd, with a bear and star (the "Bear Flag") to symbolize that they had taken control

June 23, 1846: John C. Fremont arrives with 60 American soldiers

June 24, 1846: The Battle of Olompali.  Mexican military commander General Jose Castro had sent Mexican troops north from the fort at Monterey, but they were defeated at the Battle of Olompali

July 7, 1846: Commodore John D. Sloat leads the American navy to victory at the Battle of Monterey and issues a proclamation announcing that California was now part of the United States. John D. Sloat was Military Governor of California for only 7 days when he handed over the office to Commodore Robert F. Stockton.

July 9, 1846: William B. Ide and the other "Bear Flaggers" joined John C. Fremont and the U.S. armed forces in taking possession of California from Mexico.

Kit Carson was a scout of John C. Fremont's California Battalion, who carried messages back to Washington on the status of hostilities in California.

July 9, 1846: The U.S. Flag Is raised at Sonoma replacing the Bear Flag. U.S. forces had taken control of northern California in less than one month month

September 25, 1846: Stephen W. Kearny set out for California on with a force of 300 men to assist in the conquest of California

January 10, 1847: 600 men consisting of Stephen Kearny's dragoons, Robert Stockton's marines, and two companies of John Fremont's California Battalion won the battles of San Gabriel and the La Mesa and retook control of Los Angeles

January 13, 1848: The Californio forces in California capitulated to John C. Fremont and his California Battalion.

January 13, 1848: The informal Treaty of Cahuenga ended the fighting of the Mexican–American War in Alta California

February 2, 1848: Mexico formally ceded Alta California and other territories to the United States under the terms of the 1848 Treaty of Guadalupe Hidalgo.

The California Gold Rush started with the discovery of gold by James W. Marshall at Sutter's Lumber Mill in Coloma on January 24, 1848, before the treaty was even signed.