The Alton Marquette Catholic Explorers play Illinois high school football (IHSA) as a 2010 member of the South Central conference. Marquette Catholic High School is located in Alton, Illinois. Alton is in Madison county. The Explorers' Illinois Pigskin region is the 618 Football Region. They are coached by Tim Nelson entering his 3rd year of coaching at Marquette Catholic. The school Athletic Director is Jerry Montague.

The schools 2010 enrollment numbers are 433.95. The Explorers' colors are Royal Blue/White. Alton Marquette Catholic has qualified for the IHSA playoffs 17 times, the last playoff appearance was 2009. They have qualified for the playoffs 4 consecutive years.