Principia College is in Elsah, Illinois, 12 miles north of Alton, Illinois, on the Great River Road, Route 100. Turn right at Elsah Road, bearing right to Mill Street. Go halfway through the village of Elsah to the first stop sign. Turn right and go up the hill to the main entrance of the College.
If you use GPS in your car, these are the coordinates for the gatehouse—Latitude: 38.9555, Longitude: -90.3475
Principia School is in Town and Country, Missouri, about 30 minutes west of St. Louis, Missouri. The school is located just off Clayton Road and is within a mile of highways 40, 64, and 270.
If you use GPS in your car, these are the coordinates for the gatehouse—Latitude: 38.627717, Longitude: -90.474043.