Pinnacle Entertainment’s new entertainment district in south St. Louis County straddles the frontier between the County and the City of St. Louis. Overlooking the Mississippi River, the site rests just south of the confluence of the Mighty Mississippi and the River des Peres. In 1700, French Jesuits established a mission in this area, which is now one of the most densely populated parts of the St. Louis Metropolitan Area, the nation’s 18th largest, with more than 2.6 million residents.