RIVER CITY CASINO & HOTEL PROPERTY FACT SHEET. LOCATION. River City Casino & Hotel is located approximately 1.5 miles from Interstate 55 at 777. River City Casino Boulevard, St. Louis, MO 63125 in Lemay, South St. Louis County. The property straddles the frontier between the County and the City of St. Louis. Overlooking the Mississippi River, River City Casino & Hotel rests just south of the.