The College of the Mainland was launched in late 1966 when the voters of Dickinson, Hitchcock, La Marque, Santa Fe, and Texas City approved a building-bond issue of $2,850,000, having been largely an idea since 1935.

In 1999, a new public service careers building opened to provide classrooms and labs for EMS, fire and police academies as well as housing the college's pharmacy technician program.

The college garnered national attention in 2002 when political-science instructor and self-avowed Marxist David Michael Smith applied for tenure, prompting vocal opposition from some residents and another former professor, Howard Katz.

The center is a leased facility that offers college credit and continuing-education classes, as well as dental-assistant, medical-assistant, and other health-care programs.

[1] In April 2010, the College of the Mainland, acting under then President Michael Elam, sought to modify the way union fees were deducted from faculty pay.

[10] Besides traditional community-college transfer classes, vocational programs, and continuing-education courses, the college offers a process-technology degree for those seeking employment as operators in the refineries and other petroleum-related plants.

COM provides free general education development (GED) and English as a second language (ESL) classes to individuals at locations throughout Galveston County.

[11] Adult basic education courses teach students reading, writing, and mathematics skills and help prepare them for the GED test.

The free ESL classes help students improve their ability to read, write, understand, and speak the English language.

COM also has a Five Star Chapter of Phi Theta Kappa, the national community-college honor society that conducts projects on campus and in the community.

In September 2007, the Texas City and Galveston chapters of the League of United Latin American Citizens accused four of the seven trustees of racism after a 4–3 vote against hiring Hispanic Juan Garcia of Tarrant County College to the post vice president of Student Services (which had been vacant for a year prior), despite a recommendation from President Hayes.