Independence was founded on March 29, 1827 and quickly became an important frontier town. Independence was the farthest point westward on the Missouri River where steamboats or other cargo vessels could travel, due to the convergence of the Kansas River with the Missouri River approximately six miles west of town, near the current Kansas-Missouri border. Independence immediately became a jumping-off point for the emerging fur trade, accommodating merchants and adventurers beginning the long trek westward on the Santa Fe Trail.
In 1831, members of the Latter Day Saint movement began moving to the Jackson County, Missouri area. Shortly thereafter, Joseph Smith, Jr., their prophet, declared a spot just west of Courthouse Square to be the place for his prophesied temple of the New Jerusalem, in expectation of the Second Coming of Christ. Tension grew with local Missourians until finally the Latter-Day Saints were driven from the area. Several branches of this movement would gradually return to the city, with many making their headquarters there. These included the Community of Christ (formerly the Reorganized Church of Jesus Christ of Latter Day Saints), the Restoration Branches and the Church of Christ (Temple Lot).
Independence saw great prosperity from the late 1830s through the mid-1840s, while the business of outfitting pioneers boomed. Between 1848 and 1868, it was a hub of the Central Route to California. On March 8, 1849, the Missouri General Assembly granted a home-rule charter to the town and on July 18, 1849, William McCoy was elected as its first mayor. In the mid-1800s an Act of the United States Congress defined Independence as the start of the Oregon Trail.
Independence saw two important battles during the Civil War: the first on August 11, 1862 when Confederate soldiers took control of the town, and the second in October 1864, which also resulted in a Southern victory. The war took its toll on Independence and the town was never able to regain its previous prosperity, although a flurry of building activity took place soon after the war. The rise of nearby Kansas City also contributed to the town's relegation to a place of secondary prominence in Jackson County, though Independence has retained its position as county seat until the present day.
President Harry S. Truman grew up in Independence, and in 1922 was elected judge of the County Court of Jackson County, Missouri (an administrative, not judicial, post). Although he was defeated for reelection in 1924, he won back the office in 1926 and was reelected in 1930. Truman performed his duties diligently, and won personal acclaim for several popular public works projects, including an extensive series of fine roads for the growing use of automobiles, the building of a new County Court building in Independence, and a series of twelve Madonna of the Trail monuments to pioneer women dedicated across the country in 1928 and 1929. He would later return to the city after two terms as President. His wife, First Lady Bess Truman, was born and raised in Independence, and both are buried there. The Truman home and the Harry S. Truman Presidential Library and Museum are both located in Independence, as is one of Truman's boyhood residences.
Independence continues to be of great importance to the Latter Day Saint movement and is the headquarters of the Community of Christ. This denomination, the second-largest in the Latter Day Saint movement, has built a striking temple in Independence, and also maintains a large auditorium and other buildings nearby. The Church of Jesus Christ of Latter-day Saints (the "Mormons") operates a sizable visitors' center adjacent to the Community of Christ Temple, which is located directly across the street from the original Temple Lot designated by Joseph Smith in 1830. The Lot itself is occupied by a small white-frame church building that serves as the headquarters and local meeting house for the Church of Christ (Temple Lot).
According to the United States Census Bureau, the city has a total area of 78.4 square miles (203.2 km²), of which, 78.3 square miles (202.9 km²) of it is land and 0.1 square miles (0.3 km²) of it (0.17%) is water.
There were 47,390 households out of which 28.1% had children under the age of 18 living with them, 47.9% were married couples living together, 12.3% had a female householder with no husband present, and 35.5% were non-families. 30.1% of all households were made up of individuals and 11.3% had someone living alone who was 65 years of age or older. The average household size was 2.37 and the average family size was 2.93.
In the city the population was spread out with 23.9% under the age of 18, 8.7% from 18 to 24, 28.9% from 25 to 44, 23.0% from 45 to 64, and 15.5% who were 65 years of age or older. The median age was 38 years. For every 100 females there were 91.6 males. For every 100 females age 18 and over, there were 87.3 males.
The median income for a household in the city was $38,012, and the median income for a family was $45,876. Males had a median income of $34,138 versus $25,948 for females. The per capita income for the city was $19,384. About 6.4% of families and 8.6% of the population were below the poverty line, including 11.8% of those under age 18 and 6.7% of those age 65 or over.
Prior to Fall 2008, parts of western Independence in the Van Horn feeder pattern resided in the Kansas City, Missouri School District, but all of these students are now part of the Independence school district.