John Fremontwas born in Savanannah, Georgia, on 21st January, 1813. Educated at Charleston College, he taught mathematics before joining the Army Topographical Engineers Corps in 1838. The following year Fremont joined a party led by Joseph N. Nicollet, that surveyed and mapped the region between the upper Mississippi and Missouri rivers.
Fremont surveyed the Des Moines River in 1841. Sponsored by the Missouri senator, Thomas Hart Benton, in 1842 Fremont mapped most of the Oregon Trail and climbed the second highest peak in the Wind River Mountains, afterwards known as Fremont Peak.
In 1843, with Kit Carson and Tom Fitzpatrick as his guides, Fremont's party followed the Cache de la Poudre River into the Laramie Mountains. He then crossed the Rocky Mountains via the South Pass and Green River. He then followed the Bear River until it reached the Great Salt Lake.
After spending time at Fort Hall he followed the Snake River past Fort Boise to Fort Vancouver, where he met John McLoughlin. Fremont then turned south where he explored Klamath Lake and the Great Basin before making a midwinter crossing of the Sierra Nevada mountains and despite great hardships reached Sutter Fort. Fremont eventually reached St. Louis on 6th August, 1844.
Fremont made his third expedition in 1845 during which he explored the Great Basin and the Pacific coast. While this was taking place the Mexican War started. Fremont was given the rank of major in the United States Army and helped annex California. Commodore Robert Stockton appointed Fremont as governor of California. However, in 1847 Fremont clashed with General Stephen Kearny and as a result was arrested for mutiny and insubordination and was subsequently court-martialed. President James Polk intervened and Fremont was eventually released.
In the winter of 1848 and 1849 Fremont led an expedition to locate passes for a proposed railway line from the upper Rio Grande to California. During the Californian Gold Rush gold was discovered on his estate and he became a multi-millionaire.
In 1850 Fremont was elected as senator for California. A strong opponent of slavery, Fremont founder member of the Republican Party. In 1856 Fremont was chosen as its first presidential candidate and although the Democratic Party candidate, James Buchanan, won with 1,838,169 votes, he did well to obtained the support of 1,335,264 electors.
When Abraham Lincoln was elected president in 1860, Fremont was expected to be appointed to the Cabinet. Lincoln was reluctant to do this and instead proposed that Fremont should be appointed minister of France. William H. Seward, Secretary of State, objected, claiming that as Fremont had been born in Georgia, he could not be trusted to remain loyal during a conflict with the South.
On the outbreak of the American Civil War Fremont was appointed as a Major General in the Union Army and put in command of the newly created Western Department based in St. Louis. On 30th August, 1861, Freemont proclaimed that all slaves owned by Confederates in Missouri were free. Abraham Lincoln was furious when he heard the news as he feared that this action would force slave-owners in border states to join the Confederate forces. Lincoln asked Fremont to modify his order and free only slaves owned by Missourians actively working for the South. Fremont refused claiming that "it would imply that I myself thought it wrong and that I had acted without reflection which the gravity of the point demanded."
Montgomery Blair, the Postmaster General,who had originally supported the appointment of Fremont, now urged Abraham Lincoln to sack him. Lincoln responded by sending Simon Cameron, Secretary of War, Congressman Elihu Washburne and General Lorenzo Thomas to investigate the situation in St. Louis. After they reported back to Lincoln he decided to relieve Fremont of his command. He was replaced by the conservative General Henry Halleck.
Horace Greeley, editor of the New York Tribune, wrote an open letter to Abraham Lincoln defending Fremont and criticizing the president for failing to make slavery the dominant issue of the war and compromising moral principles for political motives. Lincoln famously replied: "My paramount object in this struggle is to save the Union, and is not either to save or destroy slavery. If I could save the Union without freeing any slave, I would do it; and if I could save it by freeing all the slaves, I would do it."
Fremont was a popular figure with Radical Republications and in March, 1862, Abraham Lincoln agreed to appoint him as the commander of the newly established Mountain Department. However, Fremont was severely criticized for failing to deal with Thomas Stonewall Jackson during his Shenandoah Valley. On 26th June, Freemont's troops came under the command of General John Pope. Fremont refused to serve under Pope and spent the rest of the war in New York.
In May, 1864 a convention of Radical Republications selected Fremont as their candidate for president. Fremont accepted the nomination and told the audience: "Today we have in this country the abuses of a military dictation without its unity of action and vigor of execution." The idea of a radical candidate standing in the election worried Abraham Lincoln and negotiations began to persuade him to change his mind. Fremont's price was the removal of his old enemy, Montgomery Blair, from the Cabinet. On 22nd September, 1864, Fremont withdrew from the contest. The following day, Lincoln sacked Blair and replaced him with the radical, William Dennison.
After the American Civil War Fremont became involved in railroad financing and building. This was a failure and he lost the fortune that he made during the Californian Gold Rush. He returned to politics when he became governor of Arizona Territory (1873-83).