Columbus is the capital, the largest, and the most populous city of the U.S. state of Ohio. Located near the geographic center of the state, Columbus is the county seat of Franklin County, although parts of the city also extend into Delaware and Fairfield counties. Named for explorer Christopher Columbus, the city was founded in 1812 at the confluence of the Scioto and Olentangy rivers, and assumed the functions of state capital in 1816. The city has a diverse economy based on education (it is home to Ohio State University, the largest university in the United States), insurance, healthcare (three major hospital systems operating in Central Ohio), retail, and technology. Acknowledged by Money Magazine as the 8th best large city in the U.S. to inhabit, it is also recognized as an emerging global city. Residents of Columbus are usually referred to as Columbusites.

The population was 711,470 at the 2000 census. Columbus is located within 550 miles of half of the United States' population. In 2006 Columbus was ranked as the 15th largest city in the United States, with 747,755 residents, and was also the 32nd largest metropolitan area, the fourth largest city in the Midwest, and the fourth most populous Capital in the U.S. The name Columbus is often used to refer to the Columbus Metropolitan Area, which includes many other municipalities. According to the US Census, the metropolitan area has a population of 1,754,337, while the Combined Statistical Area (which also includes Marion and Chillicothe) has 1,982,252 people.

Evidence of ancient mound-building societies abounds in the region near the confluence of the Scioto and Olentangy rivers. Mound Street, located in downtown Columbus, was so named because of its proximity to a large Native American burial mound. Numerous other earthworks were found throughout the area, including a surviving edifice on McKinley Avenue. Those ancient civilizations had long since faded into history when European explorers began moving into the region south of Lake Erie.

Rather than an empty frontier, however, they encountered people of the Miami, Delaware, Wyandot, Shawnee, and Mingo nations. These tribes resisted expansion by the fledgling United States, resulting in years of bitter conflict. A decisive battle at Fallen Timbers resulted in the Treaty of Greenville, which finally opened the way for new settlements. By 1797, a young surveyor from Virginia named Lucas Sullivant had founded a permanent settlement on the west bank of the forks of the Scioto River. An admirer of Benjamin Franklin, Sullivant chose to name his new frontier village "Franklinton." Although the location was desirable in its proximity to navigable rivers, Sullivant was initially foiled when, in 1798, a large flood wiped out the newly formed settlement. He persevered, and the village was rebuilt.

After Ohio achieved statehood in 1803, political infighting among Ohio's more prominent leaders resulted in the state capital moving from Chillicothe to Zanesville and back again. The state legislature finally decided that a new capital city, located in the center of the state, was a necessary compromise. Several of Ohio's small towns and villages petitioned the legislature for the honor of becoming the state capital, but ultimately a coalition of land speculators, with Sullivant's support, made the most attractive offer to the Ohio General Assembly. Named in honor of Christopher Columbus, the capital city was founded on February 14, 1812, on the "High Banks opposite Franklinton at the Forks of the Scioto known as Wolf's Ridge." At the time, this area was a dense forestland, used only as a hunting ground.

The Burough of Columbus was officially established on February 10, 1816. Nine people were elected to fill the various positions of Mayor, Treasurer, and others. Although the recent War of 1812 had brought prosperity to the area, the subsequent recession and conflicting claims to the land threatened the success of the new town. Early conditions were abysmal with frequent bouts of fevers and an outbreak of cholera in 1833.

The National Road reached Columbus from Baltimore in 1831, which complemented the city's new link to the Ohio and Erie Canal and facilitated a population boom. A wave of immigrants from Europe resulted in the establishment of two ethnic enclaves on the outskirts of the city. A significant Irish population settled in the north along Naghten Street (presently Nationwide Boulevard), while the Germans took advantage of the cheap land to the south, creating a community that came to be known as Das Alte Südende (The Old South End). Columbus' German population is responsible for constructing numerous breweries, Trinity Lutheran Seminary, and Capital University.

With a population of 3500, Columbus was officially chartered as a city on March 3, 1834. The legislature carried out a special act on that day, which granted legislative authority to the city council and judicial authority to the mayor. Elections were held in April of that year, with voters choosing one John Brooks as the first mayor.

In 1850 the Columbus and Xenia Railroad became the first railroad to enter the city, followed by the Cleveland, Columbus and Cincinnati Railroad in 1851. The two railroads built a joint Union Station on the east side of High Street just north of Naghten (then called North Public Lane). Rail traffic into Columbus increased—by 1875 Columbus was served by eight railroads, and a new, more elaborate station was built.

On January 7, 1857, the Ohio Statehouse finally opened to the public after eighteen years of construction.

During the Civil War, Columbus was a major base for the volunteer Union Army that housed 26,000 troops and held up to 9,000 Confederate prisoners of war at Camp Chase located at what is now the Hilltop neighborhood of west Columbus. Over 2,000 Confederate soldiers remain buried at the site, making it one of the largest Confederate cemeteries in the North. North of Columbus, along the Delaware Road, the Regular Army established Camp Thomas, where the 18th U.S. Infantry was organized and trained.

By virtue of the Morrill Land-Grant Colleges Act, the Ohio Agricultural and Mechanical College was founded in 1870 on the former estate of William and Hannah Neil.

By the end of the 19th century, Columbus saw the rise of several major manufacturing businesses. The city became known as the "Buggy Capital of the World," thanks to the presence of some two dozen buggy factories, notably the Columbus Buggy Company, which was founded in 1875 by C.D. Firestone. The Columbus Consolidated Brewing Company also rose to prominence during this time, and it may have achieved even greater success were it not for the influence of the Anti-Saloon League, based in neighboring Westerville. In the steel industry, a forward-thinking man named Samuel P. Bush presided over the Buckeye Steel Castings Company. Columbus was also a popular location for the organization of labor. In 1886, Samuel Gompers founded the American Federation of Labor in Druid's Hall on S. Fourth Street, and in 1890 the United Mine Workers of America was founded at old City Hall.

Columbus earned its nickname "The Arch City" because of the dozens of metal (formerly wooden) arches that spanned High Street at the turn of the twentieth century. The arches illuminated the thoroughfare and eventually became the means by which electric power was provided to the new streetcars. The arches were torn down and replaced with cluster lights in 1914, but were reconstructed in the Short North district in 2002 for their unique historical interest.

On March 25, 1913, a catastrophic flood devastated the neighborhood of Franklinton, leaving over ninety people dead and thousands of West Side residents homeless. To prevent future flooding, the Army Corps of Engineers recommended widening the Scioto River through downtown, constructing new bridges, and building a retaining wall along its banks. With the strength of the post-WWI economy, a construction boom occurred in the 1920s, resulting in a new Civic Center, the Ohio Theatre, the American Insurance Union Citadel, and, to the north, a massive new Ohio Stadium. Although the American Professional Football Association was founded in Canton in 1920, its head offices moved to Columbus in 1921 and remained in the city until 1941. In 1922, the association's name was changed to the National Football League. The same year, Coats Steam Car set up shop in Columbus, only to move to Bowling Green and ultimately fail.

The effects of the Great Depression were somewhat less severe in Columbus, as the city's diversified economy helped it fare marginally better than its Rust Belt neighbors. World War II brought a tremendous number of new jobs to the city, and with it another population surge. This time, the majority of new arrivals were migrants from the "extraordinarily depressed rural areas" of Appalachia, who would soon account for more than a third of Columbus' rising population. In 1948, the Town and Country Shopping Center opened in suburban Whitehall, and it is now regarded as one of the first modern shopping centers in the United States. Along with the construction of the interstate highway, it signaled the arrival of rapid suburban development in central Ohio. In order to protect the city's tax base from this suburbanization, Columbus adopted a policy of linking sewer and water hookups to annexation to the city. By the early 1990s, Columbus had grown to become Ohio's largest city in both land area and in population.

Efforts to revitalize Downtown Columbus have met with mixed results in recent decades. In the 1970s old landmarks such as Union Station and the Neil House Hotel were razed to construct high-rise offices and retail space such as the Huntington Center. Newer suburban developments at Tuttle Crossing, Easton, and Polaris have inhibited much of the anticipated downtown growth. Still, with the addition of the Arena District, as well as hundreds of downtown residential units, significant revitalization efforts are likely to continue in the downtown area.