St. Charles is a city in, and the county seat of, St. Charles County, Missouri

Saint Charles County, Missouri

As of 2000, there were 283,883 people, 101,663 households, and 77,060 families residing in the county. The population density was 507 people per square mile . There were 105,514 housing units at an average density of 73 persons/km²...

. As of the 2010 census, the city had a population of 65,794, making St. Charles the 2nd largest city in St. Charles County. It lies just to the northwest of St. Louis, Missouri

St. Louis, Missouri

St. Louis is an independent city on the eastern border of Missouri, United States. With a population of 319,294, it was the 58th-largest U.S. city at the 2010 U.S. Census. The Greater St...

 on the Missouri River

Missouri River

The Missouri River flows through the central United States, and is a tributary of the Mississippi River. It is the longest river in North America and drains the third largest area, though only the thirteenth largest by discharge. The Missouri's watershed encompasses most of the American Great...

, and, for a time, played a significant role in the United States' westward expansion. It is the third oldest city west of the Mississippi, founded in 1765 as Les Petites Côtes, "The Little Hills", by Louis Blanchette

Louis Blanchette

Louis Blanchette was a French Canadian explorer who travelled to North America in the 18th century. After exploring parts of Missouri, he is remembered for founding the city of St...

, a French Canadian fur trader, and was the last "civilized" stop for the Lewis and Clark Expedition

Lewis and Clark Expedition

The Lewis and Clark Expedition, or ″Corps of Discovery Expedition" was the first transcontinental expedition to the Pacific Coast by the United States. Commissioned by President Thomas Jefferson and led by two Virginia-born veterans of Indian wars in the Ohio Valley, Meriwether Lewis and William...

 in 1804.