High Quality Content by WIKIPEDIA articles! The Baldwin School is an all-girls private day school located in Bryn Mawr, Pennsylvania. The school, founded in 1888 by Florence Baldwin, consists of a Lower, Middle, and Upper School totaling approximately 600 in enrollment. The Baldwin School is located in a national historic site, a 19th century residence designed by Frank Furness that formerly served as a hotel, and is a landmark of the Pennsylvania Main Line.