St. Charles is a city in, and the county seat of, St. Charles County, Missouri. It lies just to the northwest of St. Louis, Missouri, on the Missouri River, and played for a time 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, a French Canadian fur trader, and was the last "civilized" stop for the Lewis and Clark Expedition in 1804. The city served as the first Missouri capital, from 1821 to 1826. It is the site for the Saint Rose Philippine Duchesne shrine. It is also the home base for the St. Louis National Weather Service Forecast Office, serving central, east-central and northeastern Missouri as well as west-central and southwest Illinois.