Merced Adult School is governed by the Merced Union High School District and approves all program courses.

Merced Adult School provides a variety of programs to meet the needs of the community. Classes are offered throughout the area, year-round, Monday through Thursday, 8 a.m. to 9 p.m. and 8 a.m. to 5 p.m. on Fridays. Classes are held at Castle Airport , as well as, in district classrooms, businesses and community centers.

The Castle Lab has an open-entry, open-exit schedule with individualized competency based programs, flexible hours, and caring instructors. These programs work well for students with childcare and transportation issues by addressing individual needs and learning styles.The GED program consists of five subjects - English, math, science, social studies and literature. The high school diploma program is an individualized program that offers all the courses necessary for the fulfillment of the high school graduation requirements (170 credits). The course work is contract-based between instructor and student.