Alfred Langdon Elwyn (9 July 1804 – 15 March 1884) was a nonpracticing physician, an author, a philanthropist and a pioneer in the training and care of mentally disabled in the US. In addition, Elwyn was one of the founding officers of the Pennsylvania Institution for the Blind in 1833, and later served as the Institution's president. Elwyn also headed a Pennsylvania agricultural society and farm school. In addition, Elwyn was president of a society for prevential of cruelty to animals. He served as treasurer of the American Association for the Advancement of Science between 1849 and 1870.
Elwyn was born in Portsmouth, New Hampshire, the grandson of John Langdon, the first continental governor of New Hampshire. Elwyn graduated from Harvard University in 1823, and studied medicine overseas from 1824-1829. He returned in 1831 and received his medical degree from the University of Pennsylvania. He never practiced medicine, but was an active philanthropist and author.
The town of Elwyn, Pennsylvania and the care and training facility Elwyn are named for Alfred Elwyn.
Elwyn travelled to Boston for a meeting of the American Association for the Advancement of Science in 1849. He had promised to take a letter from Rachel Laird, a blind girl living in Philadelphia, to Laura Bridgman (December 21, 1829 - May 24, 1889), who was a famous blind deaf mute in Boston. Bridgman was studying at the South Boston Institute for the Blind, and while there Elwyn visited a classroom for mentally deficient children run by teacher James Richards.
Elwyn was impressed with Richards' work, and resolved to do something similar in Pennsylvania. In 1852, with Richards, Elwyn established a training school for the retarded in Germantown, Pennsylvania. In 1853, the Pennsylvania State Legislature formally chartered "The Pennsylvania Training School for Feeble-Minded Children" with Richards as its first superintendent in Germantown. The school soon outgrew its facilities in Germantown, and in 1857 a 60-acre (240,000 m2) farm was purchased in Media, Pennsylvania to house a new facility with help from the Pennsylvania legislature. The buildings were completed in 1859 and Elwyn, Richards and 25 students moved in on September 1, 1859. The school was officially dedicated November 2, 1859. Elwyn became head of the school in 1870.