The campus of St. John Interparochial School is contained in a one block area of a residential section of the City of Plaquemine, LA. The campus consists of the high school building, the middle school building, and the elementary building. The main office is located in the middle school building. 

The campus also includes: the St. John Gym, the St. John Cafeteria, St. Clement of Rome Chapel, the Jerome Dugas Athletic Building, and the St. John Field House. The athletic facilities located on the campus are the St. John Baseball Field, Softball Field, and a practice field located on the western end of the campus. An additional building, formerly dedicated as the St. Clement of Rome Rectory, is located adjacent to St. Clement Chapel. It presently houses the ACE – Alliance for Catholic Education – teachers that are employed at St. John.

In 2019, the gym was renovated and a perimeter fence was added, enclosing the main areas of the campus. New technology has also been added to the facilities. Renovations and updates are ongoing to continue meeting the needs of our students.