James Polk was the 11th president of the United States, known for his territorial expansion of the nation chiefly through the Mexican-American War.

James Polk was born in 1795 in North Carolina, and went on to become the 11th and youngest (at the time) president of the United States (1845–1849). Polk’s annexation of Texas led to the Mexican-American War (1846–1848), and the U.S. victory thereby led to the acquisition of large territories in the Southwest and along the Pacific coast, which in turn led to the establishment of the Department of the Interior. The northern border of the United States was also established under Polk, as were the Naval Academy and the Smithsonian. He died on June 15, 1849, in Nashville, Tennessee.

Early Years
James Knox Polk was born in Pineville, a small town in Mecklenburg County, North Carolina, on November 2, 1795, and graduated with honors in 1818 from the University of North Carolina. Leaving his law practice behind, he served in the Tennessee legislature, where he became friends with Andrew Jackson. Polk moved from the Tennessee legislature to the United States House of Representatives, serving from 1825 to 1839 (and serving as speaker of the House from 1835 to 1839). He left his congressional post to become governor of Tennessee.

Approaching the Presidency
Leading into the presidential election of 1844, Polk was the frontrunner for the Democratic nomination for the vice presidency. Both would-be presidential candidates, Martin Van Buren for the Democrats and Henry Clay for the Whigs, sought to skirt the expansionist (“manifest destiny”) issue during the campaign, seeing it as potentially controversial. The first step in distancing their campaigns was declaring opposition to the annexation of Texas. Polk, on the other hand, took a hard stance on the issue, insisting on the annexation of Texas and, in a roundabout way, Oregon.

Enter Andrew Jackson, who knew that the American public favored westward expansion. He sought to run a candidate in the election committed to the precepts of manifest destiny, and at the Democratic Convention, Polk was nominated to run for the presidency. Polk went on to win the popular vote by a razor-thin margin, but took the electoral college handily.

Presidency and Expansionism
James Polk took office on March 4, 1845—and, at 49 years of age, he became the youngest president in American history. Before Polk took the oath of office, Congress offered annexation to Texas, and when they accepted and became a new state, Mexico severed diplomatic relations with the United States and tensions between the two countries escalated.

Regarding the Oregon territory, which was much larger than the current state of Oregon, President Polk would have to contend with England, who had jointly occupied the area for nearly 30 years. Polk’s political allies claimed the entire Oregon area for the United States, from California northward to the 54° 40′ latitude (the southern boundary of what is now Alaska), and so the mantra “54-40 or fight!” was born. Neither England nor the Polk administration wanted a war, and Polk knew that only war would likely allow the United States to claim the land.

After back-and-forth negotiation, and some effective hard ball played by Polk, the British accepted the 49th parallel as the northern border (the current border between the United States and Canada), excluding the southern tip of Vancouver Island, and the deal was sealed in 1846.

Things went less smoothly in the hunt for California and New Mexico, and ever-increasing tensions led to the Mexican-American War. After several battles and the American occupation of Mexico City, Mexico ceded New Mexico and California in 1848, and coast-to-coast expansion was complete.

• James Knox Polk was the 11th president of the United States, serving from 1845 to 1849. He previously was Speaker of the House of Representatives and governor of Tennessee. A protégé of Andrew Jackson, he was a member of the Democratic Party and an advocate of Jacksonian democracy.
• Born: November 2, 1795, Pineville, NC
• Died: June 15, 1849, Nashville, TN
• Presidential term: March 4, 1845 – March 4, 1849
• Party: Democratic Party
• Vice president: George M. Dallas (1845–1849)
• Buried: Tennessee State Capitol, Nashville, TN
• First president to be elected to the office before reaching the age of 50 (49).
• First president to be under the age of 50 upon entering office.
• First president to have served as speaker of the House of Representatives.
• First president born in North Carolina.
• First president to be a Methodist.
• First president to be elected despite losing his states of birth and residence.
• First president to be nominated by his party as a dark horse.
• First president not to seek re-election upon the completion of his one term.
• First president to die before reaching the age of 60.
• First president to predecease a parent.
• First president not to keep a pet during his term in office.