Tulsa (pronounced /'t?ls?/) is the second largest city in the state of Oklahoma and 46th-largest city in the United States. With an estimated population of 385,635 in 2008, it is the principal municipality of the Tulsa Metropolitan Statistical Area, a region of 916,079 residents projected to reach one million between 2010 and 2012. In 2008, the Tulsa-Bartlesville Combined Statistical Area had a population of 966,531 residents. The city serves as the county seat of Tulsa County, the most densely populated county in Oklahoma, and extends into Osage, Rogers, and Wagoner counties.

Tulsa was first settled in the 1830s by the Lachapoka Band of Creek Native American tribe. In 1921, it was the site of the infamous Tulsa Race Riot, one of the largest and most destructive acts of racial violence in the history of the United States. For most of the 20th century, the city held the nickname "Oil Capital of the World" and played a major role as one of the most important hubs for the American oil industry. Tulsa, along with several other cities, claims to be the birthplace of U.S. Route 66. Tulsa is also known for its Western Swing music.

Once heavily dependent on the oil industry, economic downturn and subsequent diversification efforts created an economic base in the energy, finance, aviation, telecommunications and technology sectors. The Tulsa Port of Catoosa, at the head of the McClellan-Kerr Arkansas River Navigation System, is the most inland river port in the U.S. with access to international waterways. Two institutions of higher education within the city operate at the NCAA Division I level, Oral Roberts University and the University of Tulsa.

Located in Tornado Alley, the city frequently experiences severe weather. It is situated on the Arkansas River at the foothills of the Ozark Mountains in northeast Oklahoma, a region of the state known as "Green Country." Considered the cultural and arts center of Oklahoma, Tulsa houses two world-renowned art museums, full-time professional opera and ballet companies, and one of the nation's largest concentrations of art deco architecture. The city has been called one of America's most livable large cities by Partners for Livable Communities, Forbes, and Relocate America. People from Tulsa are called "Tulsans."

What was ultimately to become Tulsa was originally part of Indian Territory and was first settled by the Lochapoka and Creek tribes in 1836. They established a home under a large oak tree at the present day intersection of Cheyenne Avenue and 18th Street, and named their new settlement "Tallasi", meaning "old town" in the Creek language, which later became "Tulsa". On January 18, 1898, Tulsa was officially incorporated and elected its first mayor, Edward Calkins.

A small town near the banks of the Arkansas River in 1901, Tulsa's first oil well, named Sue Bland No. 1, was established that year. By 1905, the discovery of the large Glenn Pool nearby (site of the present day town of Glenpool) prompted a rush of entrepreneurs to the area's growing number of oil fields; Tulsa's population swelled to over 140,000 between 1901 and 1930. By 1909, seven years after the discovery of oil in the area, Tulsa's population had sprouted to 18,000. Known as the "Oil Capital of the World" for most of the 20th century, the city's success in the energy industry prompted construction booms in the popular Art Deco style of the time. Profits from the oil industry continued through the Great Depression, helping the city's economy fare better than most in the United States during the 1930s.
 
Cain's Ballroom came to be known as the "Carnegie Hall of Western Swing" in the early 20th century.In the early 20th century, Tulsa was home to the "Black Wall Street," one of the most prosperous African American communities in the United States at the time. Located in the Greenwood neighborhood, it was the site of the Tulsa Race Riot, one of the nation's costliest acts of racial violence and civil disorder. Sixteen hours of rioting on May 31 and June 1, 1921 resulted in over 800 people admitted to local hospitals with injuries, an estimated 10,000 left homeless, 35 city blocks composed of 1,256 residences destroyed by fire, and $1.8 million in property damage. Twenty-three black and 16 white citizens were reported killed, but estimates suggest as many as 300, mostly blacks, died.

In 1925, Tulsa businessman Cyrus Avery, known as the "Father of Route 66," began his campaign to create a road linking Chicago to California by establishing the U.S. Highway 66 Association in Tulsa, earning the city the nickname the "Birthplace of Route 66." Once completed, U.S. Route 66 took an important role in Tulsa's development as the city served as a popular rest stop for travelers, who were greeted by Route 66 icons such as the Meadow Gold Sign and the Blue Whale of Catoosa. During this period, Bob Wills and his group The Texas Playboys began their long performing stint at a small ballroom in downtown Tulsa. In 1935, Cain's Ballroom became the base for the group, which is largely credited for creating Western Swing music. The venue continued to attract famous musicians through its history, and is still in operation today. For the remainder of the mid-20th century, a master plan called for the construction of parks, churches, museums, rose gardens, improved infrastructure, and increased national advertising. The Spavinaw Dam, built during this era to accommodate the city's water needs, was considered one of the largest public works projects of the era. In the 1950s, Time magazine dubbed Tulsa "America's Most Beautiful City."

A national recession greatly affected the city's economy in 1982, as areas of Texas and Oklahoma heavily dependent on oil witnessed a freefall in gas prices and a mass exodus of oil industries. Tulsa, heavily dependent on the oil industry, was one of the hardest hit cities by the fall of oil prices. By 1992, the state's economy had fully recovered, but leaders would attempt to expand into sectors unrelated to oil and energy.

In 2003, the "Vision 2025" program was approved by voters with the purpose of enhancing and revitalizing Tulsa's infrastructure and tourism industry. The keystone project of the initiative, the BOK Center, was designed to be a home for the city's minor league hockey and arena football teams, as well as a venue for major concerts and conventions. The multi-purpose arena, designed by famed architect Cesar Pelli, broke ground in 2005 and was opened on August 30, 2008.