The history of St. Louis began with the settlement of the area by Native American mound builders who lived as part of the Mississippian culture from the 9th century to the 15th century, followed by other migrating tribal groups. Starting in the late 17th century, French explorers arrived. Spain took over in 1763 and a trading company led by Pierre Laclede and Auguste Chouteau established the settlement of St. Louis in February 1764. It attracted French settlers leaving Illinois after their defeat in the Seven Years' War. The city grew in population due to its location as a trading post on the Mississippi River, as the western fur trade was lucrative. The city played a small role in the American Revolutionary War and became part of the U.S. through the Louisiana Purchase in 1803.

With its connection through the Ohio River to the east, the Mississippi to the south and north, and the Missouri to the west, St. Louis was ideally located to become the main base of interregional trade. In the 1840s, it became a destination for massive immigration by Irish and Germans. Some native-born Americans reacted with fear to the newcomers, adopting nativist sentiments. Missouri was a slave state, but the city's proximity to free states caused it to become a center for the filing of freedom suits. Many slaves gained freedom through such suits in the antebellum years. But, by the 1850s and the Dred Scott case, interpretations had changed and the US Supreme Court ruled against him. It also ruled that the Missouri Compromise was unconstitutional, contributing to the tensions causing the American Civil War. During the War, St. Louis had a small skirmish on its outskirts, but was held under Union control.

After the war, the city expanded its railroad connections and industrial activity. It suffered a corresponding rise in pollution of the river and waterfront. During the early 1870s, the Eads Bridge was constructed over the Mississippi River, and the city established several large parks, including Forest Park. Due to local political and economic disputes, the city separated from St. Louis County in 1876 and became an independent city. During the late 19th century, St. Louis became home to two Major League Baseball teams. Ragtime and blues music flourished in the city, with African Americans making major contributions also in jazz.

The city hosted the 1904 World's Fair and the 1904 Summer Olympics, attracting millions of visitors. Part of the infrastructure for the fair was the basis for major city institutions in Forest Park. In the early part of the century, many African Americans migrated from the South to the city for industrial jobs, as part of the Great Migration. St. Louis did not escape the Great Depression and its high unemployment. During World War II the city hosted war industries that employed thousands of workers.

After the war, federal highway subsidies and postwar development encouraged outward migration as residents moved to gain newer housing; this suburbanization significantly reduced the city's middle-class population. The city made efforts to create new attractions, such as the Gateway Arch, which construction became a focus of the civil rights movement to gain desegregated jobs in the skilled trades. The first litigation under the 1964 Civil Rights Act was against St. Louis unions. The city worked to replace substandard housing by new public housing projects such as Pruitt–Igoe. A combination of factors resulted in this being notoriously unsuccessful, and it was demolished in the late 20th century. Starting in the 1980s and continuing into the following century, construction and gentrification have increased in some areas of St. Louis, particularly downtown. City beautification and crime reduction have made progress, although St. Louis has continued to struggle with crime and perceptions of crime. The city saw modest population growth during the mid-2000s, but showed a decline in the 2010 U.S. census.

Exploration and Louisiana before 1762

The earliest settlements in the middle Mississippi Valley were built in the 10th century by the people of the Mississippian culture, who constructed more than two dozen platform mounds within the area of the future European-American city.Primm (1998), 1.Peregrine (1996), xx. These were related to the center of the culture at the very large complex of Cahokia Mounds, on the east side of the Mississippi River. The Mississippian culture ended for unknown reasons in the 14th century and these sites were empty for some time. Native American tribes such as the Missouria and the Osage migrated from the eastern Ohio Valley to the Missouri Valley. They lived in villages along the Missouri and Osage rivers. Both groups competed with northeastern tribes such as the Sauk and the Meskwaki, and all four groups confronted the earliest European explorers of the middle Mississippi Valley.

Extensive European exploration near the confluence of the Missouri and Mississippi rivers began nearly a century before the city was officially founded.Primm (1998), 2. Explorer Louis Joliet and Jesuit priest Jacques Marquette traveled south on the Mississippi River in June 1673, passed the future site of St. Louis and reached the mouth of the Arkansas River before turning back.Primm (1998), 3.Shepard (1870), 10.

Nine years later, French explorer La Salle led an expedition south from the Illinois River to the mouth of the Mississippi in the Gulf of Mexico, claiming the entire valley for France. La Salle named the Mississippi river basin La Louisiane (Louisiana) after King Louis XIV; the region between and near the confluence of the Ohio and Mississippi rivers was named the Illinois Country. As part of a series of forts in the Mississippi valley, the French built settlements at Cahokia and Kaskaskia, Illinois. French trading companies also built towns during the 1720s and 1730s, including Fort de Chartres and Ste. Genevieve, Missouri, the first European town in Missouri west of the Mississippi.Primm (1998), 5.Shepard (1870), 11. From 1756 to 1760, fighting in the French and Indian War (the North American front of the Seven Years' War) halted settlement building. The economy remained weak through 1762 due to the ongoing war, which France lost the following year.Foley and Rice (1983), 4.Primm (1998), 8.

City founding and early history: 1763–1803

The arrival in New Orleans of Jean-Jacques Blaise d'Abbadie as the new governor of Louisiana in June 1763 led to changes in colonial policies. D'Abbadie quickly moved to grant trade monopolies in the middle Mississippi Valley to stimulate the economy. Among the new monopolists was Pierre Laclede, who along with his stepson Auguste Chouteau set out in August 1763 to build a fur trading post near the confluence of the Missouri and Mississippi rivers. The settlement of St. Louis was established at a site south of the confluence on the west bank of the Mississippi on February 15, 1764, by Chouteau and a group of about 30 men.Primm (1998), 9.Foley and Rice (1983), 5. Laclede arrived at the site by mid-1764 and provided detailed plans for the village, including a street grid and market area.Primm (1998), 10.

French settlers began to arrive from settlements on the east bank of the Mississippi in 1764, given the transfer of eastern land to Great Britain after the Treaty of Paris.Foley and Rice (1983), 6. The local French lieutenant governor moved to St. Louis in 1765 and began awarding land grants.Primm (1998), 15. As part of the peace negotiations to end the Seven Years' War, Spain gained control of Louisiana according to the secret Treaty of Fontainebleau in 1762.Primm (1998), 17. Due to travel times and the Louisiana Rebellion of 1768, the Spanish took official control in St. Louis only in May 1770.Primm (1998), 22.Shepard (1870), 14. After the transfer, the Spanish confirmed French land grants, and Spanish soldiers provided local security.Primm (1998), 23.Shepard (1870), 15.

The occupation of most settlers was farming, and by the 1790s nearly were under cultivation around St. Louis. Fur trading was the major commercial focus of many residents, as it was much more lucrative than agriculture during that period. The residents were not particularly religious, in spite of their Roman Catholic faith.Primm (1998), 31. The first church was constructed in mid-1770 and St. Louis acquired a resident priest in 1776, making Catholic religious observance a more customary component of life.Primm (1998), 33.Shepard (1870), 19.

The French settlers brought both black and Indian slaves to St. Louis; although the majority were used as domestic servants, others worked as agricultural laborers.Van Ravenswaay (1991), 66. In 1769, the Spanish prohibited Indian slavery in Louisiana, but the practice was entrenched among the French Creoles in St. Louis. As a compromise, Spanish governors ended the Indian slave trade but allowed the retention of current slaves and any children born to them.Primm (1998), 24. In 1772, a census determined the population of the village to be 637, including 444 whites (285 males and 159 females) and 193 African slaves, with no Indian slaves reported due to their technical illegality.Primm (1998), 25. During the 1770s and 1780s, St. Louis grew slowly and the Spanish commanders were replaced often.Primm (1998), 27.

American Revolutionary War

Upon the beginning of the American Revolutionary War, Spanish governor, Bernardo de Galvez, in New Orleans assisted the American rebels with weapons, food, blankets, tents and ammunition.Primm (1998), 37. The Spanish lieutenant governors at St. Louis also aided the Americans, particularly the forces of George Rogers Clark during the Illinois campaign. After the official entry of Spain into the American Revolutionary War in June 1779 on the side of the Americans and the French, the British began preparing an expedition to capture St. Louis and other Mississippi outposts.Drumm (1931), 642. However, the city was warned of the plans, and residents began to fortify the town.Drumm (1931), 643.

On May 26, 1780, a British commander leading a force consisting mostly of Indian allies launched an assault on the town of St. Louis, but were forced to retreat due to the fortifications constructed by the locals and defections of some of the Indians.Drumm (1931), 644. In spite of the failure of their expedition, the Indians managed to torch much of St. Louis' agricultural lands and capture several heads of livestock, alongside several prisoners of war.Drumm (1931), 647. A subsequent counterattack launched from the settlers against British forts in the Midwest ended the possibility of another attack being launched on the town.Drumm (1931), 649.

After the conclusion of the Revolutionary War at the Treaty of Paris, French Creole families evading American rule moved to the Spanish-controlled land on the west bank, including wealthy merchants Charles Gratiot, Sr. and Gabriel Cerre.Primm (1998), 46. Both the Gratiot and Cerre families intermarried with the Chouteau family to create a Creole-dominated society in the 1780s and 1790s. The families also had marital ties to Spanish government officials, including the lieutenant governors Piernas and Cruzat.Primm (1998), 51.

Transfer to France and the United States

During the 1790s, towns near St. Louis expanded as small farmers sold their lands to the Cerres, Gratiots, Soulards, or Chouteaus. These farmers moved to towns such as Carondelet, St. Charles, and Florissant. By 1800, only 43% of the district's population lived within the village (1,039 of 2,447).Primm (1998), 63.