John C. Frémont, American general, explorer, and politician, 5th Territorial Governor of Arizona (d. 1890)
John Charles Frémont or Fremont (January 21, 1813 – July 13, 1890) was an explorer of the Western United States, military officer, and politician. He was a U.S. Senator from California, and in 1856 was the first Republican nominee for President of the United States and founder of the California Republican Party when he was nominated.

A native of Georgia, he was an opponent of slavery. In the 1840s, Frémont led five expeditions into the Western United States. While on the third expedition, he and his men committed a number of massacres against Native Americans in California. During the Mexican–American War, Frémont, a major in the U.S. Army, took control of California from the California Republic in 1846. Frémont was convicted in court-martial for mutiny and insubordination after a conflict over who was the rightful military governor of California. After his sentence was commuted and he was reinstated by President Polk, Frémont resigned from the Army. Afterwards, Frémont settled in California at Monterey while buying cheap land in the Sierra foothills. When gold was found on his Mariposa ranch, Frémont became a wealthy man during the California Gold Rush. Frémont became one of the first two U.S. senators elected from the new state of California in 1850. Frémont was the first presidential candidate of the new Republican Party, carrying most of the North. He lost the 1856 presidential election to Democrat James Buchanan when Know Nothings split the vote.

At the beginning of the American Civil War in 1861, he was given command of Department of the West by President Abraham Lincoln. Although Frémont had successes during his brief tenure there, he ran his department autocratically, and made hasty decisions without consulting President Lincoln or Army headquarters. He issued an unauthorized emancipation edict and was relieved of his command for insubordination by Lincoln. After a brief service tenure in the Mountain Department in 1862, Frémont resided in New York, retiring from the Army in 1864. Frémont was nominated for president in 1864 by the Radical Democracy Party, a breakaway faction of abolitionist Republicans, but he withdrew before the election. After the Civil War, Frémont lost much of his wealth in the unsuccessful Pacific Railroad in 1866, and lost more in the Panic of 1873. Frémont served as Governor of Arizona from 1878 to 1881. After his resignation as governor, Frémont retired from politics and died destitute in New York City in 1890.

Historians portray Frémont as controversial, impetuous, and contradictory. Some scholars regard him as a military hero of significant accomplishment, while others view him as a failure who repeatedly defeated his own best purposes. The keys to Frémont's character and personality, several historians argue, lie in his having been born illegitimate, and in his ambitious drive for success, self-justification and passive–aggressive behavior. His direct involvement in the California genocide of Native Americans has also diminished his historical reputation. A biographer, Allan Nevins, wrote that Frémont lived a dramatic life, of remarkable successes and dismal failures.