grounds is Eliestoun House, designed by Alexander Wadsworth Longfellow Jr. and completed in 1890. When Principia began moving to Elsah, guests stayed there, including Mary Kimball Morgan and Bernard Maybeck.
In 1934, Principia College graduated its first class as a full four-year institution. In 1935, the college was officially moved to its present-day location in Elsah. The Principia College campus was once considered as the site for the United States Air Force Academy though ultimately the Air Force chose a location in Colorado Springs, Colorado, instead.
On April 19, 1993, about 300 acres (120 ha) of the campus was designated a National Historic Landmark by the United States Department of the Interior. The year 1998 marked centennial celebrations by the school.
In the 21st century, the school's enrollment size has declined due to the dwindling number of Christian Scientists. As of 2024, the school began accepting students with no affiliation with Christian Science.
== Campus ==
=== Housing and student …
