In east-central Missouri, on the Mississippi River just south of the Missouri River
12,626.08 kilometres (7,845.5 miles)Source: True Knowledge
http://www.nps.gov/jeff/planyourvisit/directions.htm
Yes, the city is also the second largest city in the state, behind Kansas City. It is on the Fourth grade Nationwide Master homework.
About 350,000 in the city proper, and about 2.8 million in the metro area.