John Charles Frémont or Fremont (January 21, 1813 – July 13, 1890), is an American military officer, explorer, and the first candidate of the anti-slavery Republican Party for the office of President of the United States.

During the 1840s, that era's penny press accords Frémont the sobriquet The Pathfinder.

He is sometimes called The Great Pathfinder.

He retires from the military and moves to the new territory of California, after leading a fourth expedition which cost ten lives seeking a rail route over the mountains around the 38th parallel in the winter of 1849.

He becomes one of the first two U.S.

Senators elected from the new state in 1850.

He is soon bogged down with lawsuits over land claims between the dispossessions of various land owners during the Mexican-American War, and the explosion of Forty-Niners immigrating during the California Gold Rush.

He loses the 1856 presidential election to Democrats James Buchanan and John C. Breckenridge when Democrats warn his election will lead to civil war.

During the American Civil War, he is given command of the armies in the west but makes hasty decisions (such as trying to abolish slavery without consulting the federal government), and is consequently relieved of his command (fired, then court martialed – receiving a presidential pardon).

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 may lie in his being born out of wedlock, ambitious drive for success, self-justification, and passive-aggressive behavior.