"[4][5] Principia sits on bluffs overlooking the Mississippi River between Alton and Grafton in the Metro East region of Southern Illinois, thirty miles north of St. Louis.

[11][12] On the Principia College 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.

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.

In the 21st century, the school's enrollment size has declined due to the dwindling number of Christian Scientists.

The first six mentioned were designed by former University of California, Berkeley professor and AIA Gold Medal winner Bernard Maybeck in 1935, as was the campus' chapel.

In an effort to ensure success with his designs and materials, he experimented with them through the creation of a small building known affectionately by Principians as the "Mistake House.

The most popular majors include mass communication, biology, sociology, anthropology, studio and fine art, and business administration.

[27] The Principia College Speaker Series has featured former United States President Barack Obama, statesman and retired four-star general Colin Powell, former United States president George H. W. Bush, former United States president Jimmy Carter, author and poet Maya Angelou, David McCullough, Elie Wiesel, actor and director Robert Duvall, Val Kilmer, Coretta Scott King, and Margaret Thatcher.

[6] There are currently 14 varsity athletic teams at Principia College of which men's sports are baseball, basketball, cross country, soccer, tennis, track & field, and rugby; and women's sports include basketball, cross country, soccer, softball, tennis, track & field and volleyball.