McDonogh School opened its doors to twenty-one scholarship boys from Baltimore on November 21, 1873. Enrollment climbed to 50 by early February 1874 and was at 125 in 1891. The 1925 school year began with 100 foundation (scholarship) boys. Four years later, enrollment skyrocketed to 429 with 237 paying tuition; for the first time, pay students outnumbered foundation/scholarship students. Throughout the war years, the school enrollment continued to increase, and by 1952 it reached 750.
As enrollment steadily grew, it impacted the organization of the school, especially as the number of students in the early grades increased. At first, the school was separated into two divisions of six grades each. It was later reorganized to 6-2-4, and then 6-3-3. Eventually, Bob Lamborn instituted the 4-4-4 structure in which the three divisions (Lower, Middle, and Upper School) had four grades each, thus reducing the number of students in each division. This reorganization resulted in the formation of one of the first middle schools in the country and paved the way for the national middle school movement.
Since the school first opened 150 years ago, enrollment has grown from 21 to 1457 students in prekindergarten to twelfth grade.
