[2] The campus has expanded greatly over the past 140 years, and became officially coeducational in 1903 with the purchase of a boarding house from Benjamin Bowden and the construction of a second floor making it Ceder Croft Hall, which in 1927 burned down during a Christmas break.

Immediately after, a fundraising campaign initiated by MCI alumni began with the intention to rebuild a residence hall.

The building today called Weymouth Hall houses the offices of Athletics and Activities, the dean of students and the dean of residential life, as well as the television studio (WMCI), the Health and Wellness Center, the Campus Bookstore, the Student Union, and classrooms for MCI's prestigious ESL (English as a Second Language) program.

Two athletic buildings have been built—Parks Gymnasium (still standing) which was finished in 1936 due to the MCI students' increased interest in athletics and in 1988 the construction of Wright Gymnasium which houses many of MCI's trophies and recognitions and a state of the art weight room and basketball court.

Maine Central Institute also has nearby greenhouses and garden spaces for science classes and clubs.

The institute has a nationally recognized[citation needed] athletic program and has produced many prominent NBA players.

The team was led by McDonald's All-American Erick Barkley and future New England Prep player of the year Chris Foxworth.