The Maryland General Assembly created the Trust in 1967: ... to conserve, improve, stimulate, and perpetuate the aesthetic, natural, health and welfare, scenic, and cultural qualities of the environment, including, but not limited to land, water, air, wildlife, scenic qualities, open spaces, buildings or any interest therein, and other appurtenances pertaining in any way to the State.

Through educational and other means, the Trust shall encourage and motivate the populace of the State and others to do so and shall promote continuing interest in and the study of these matters.

[1]The mission of the Maryland Environmental Trust is to provide landowners with information and tools to permanently protect natural, historic and scenic resources in the state.

Some of the properties that the MET currently protects through conservation easements include Sagamore Farm, Holly Hill, Summerseat Farm, Mount Harmon, Daniel Sheffer Farm, Tyrconnell (Towson, Maryland), Maidstone (Owings, Maryland), the Smithsonian Environmental Research Center (SERC), Wye House in Talbot County and over 8,000 acres (3,200 ha) of historic land surrounding the Civil War battlefields of Antietam, Monocacy, South Mountain and the Battle of Crampton's Gap.

The remaining three trustees are ex-officio members: the Governor, Speaker of the House, and President of the Senate.