St. Charles area is located across the Missouri River west of St. Louis. St. Charles County is Missouri's third-most populous county. It is the wealthiest county in Missouri and one of the nation's fastest-growing counties.

St. Charles County includes an area of vineyards and wineries whose distinction has been nationally recognized. On its rural outer edge along the south-facing bluffs above the Missouri River is an area of numerous wineries, so that Missouri Route 94 is sometimes called the Missouri Weinstrasse. The area includes the Augusta AVA, designated in 1980 as the first American Viticultural Area by the federal government.