Rex Mundi was located at 3501 N. First Avenue, Evansville, IN 47710. It opened in the fall of 1958 in a rapidly expanding area close to what was then the north city limits of Evansville. The Country Club Meadows and Country Club Manor subdivisions opened in the early to mid 1950s in the immediate vicinity of the Rex Mundi site. At the time of the opening of the high school, the Diocese of Evansville maintained a strict policy requiring those registered in Catholic parishes to send their children to Diocesan schools. While it required an entrance exam for admissions (and exempted those who failed from the required attendance in the Catholic High School system), Rex Mundi benefited from the Diocesan attendance policy and soon was full to overflowing.