Lillian Welsh graduated from Millersville in 1873 and continued her education at the Women’s Medical College in Philadelphia. Welsh began her teaching career as a professor of anatomy, physiology, hygiene, and physical training at the Women’s College of Baltimore. There she was appointed the medical advisor to the college in 1909. She became a champion of the public health movement in Maryland and the nation. Her work resulted in the Maryland Plan, which was ultimately adopted in other states as a method of preventing the spreading of deceases. She initially served as the only female member of the Executive Committee of the Maryland Society of Social Hygiene. She was also active in the suffrage movement and the movement to extend educational opportunities to women. She was the first woman to serve on the Baltimore School Board.