High Quality Content by WIKIPEDIA articles! St. Charles County is a county located in the U.S. state of Missouri. As of 2000, the population was 283,883. The estimated 2008 population is 349,407, making it the fourth most populated county in Missouri. Saint Charles County is part of the St. Louis Metro Area. Its county seat is Saint Charles. It contains many of the northern suburbs of St. Louis as well as more exurban areas. The county was organized in 1812 and named for the Italian cardinal Saint Charles Borromeo. The wealthiest county in Missouri, St. Charles County is one of the fastest growing counties in the nation, with a population of 349,407 in 2008. It also includes an important area of vineyards and wineries whose distinction has been recognized. On its rural outer edge along the south-facing bluffs above the Missouri River is an area of numerous wineries, so that SH 94 is sometimes called the Missouri Weinstrasse.