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Principia School

At a Glance

Principia is celebrating 125 years of progressive excellence and accomplishment. See how we continue to shape 21st-century changemakers, leaders, and lifelong learners. 

Campus and Facilities


acres of woods, ponds, gardens, and trails used for outdoor learning



innovative, STEM-focused SMART® Labs supporting Preschool-twelfth grade

  • 7,477 square feet of science-lab space in the Upper School
  • 4 permaculture gardens and 1 greenhouse 
  • 12,000 square feet Performing Arts Center for band, choir, dance, and theater 
  • 2 IDEA Centers with more than 33,018 books
  • 4 performing arts stages 
  • 2 art studios
  • 3 dance studios
  • 15 instrumental and vocal practice rooms
  • 87,000 square foot high-performance athletic field house 

Students and Faculty


U.S. states and 14 foreign countries represented in the student body


of faculty hold advanced degrees

  • 457 students
  • 200 hours per teacher devoted to in-house professional development each year
  • 23% ​of the student population are students of color 
  • 60% of Principia students receive financial aid 
  • 25% of students board at Principia 
  • 45% of boarding students are international



AP and/or college-credit courses offered in Upper School


student-teacher ratio


STEM projects completed in a semester per student

  • 95% of students attend college/university
  • 3 Learning Engagement Centers
  • Average number of trips Principia students participate in during their education
    • 5 for all Upper School students with up to 6 additional trips

    • 3 Middle School, additional local field trips

    • 1 Lower School national trip, dozens of local field trips



performing-arts opportunities for students each year 


of students receive instruments and supplies from Principia 

  • 7 days Middle School students take to pull together “Theater Week” performance each year
  • 6 band ensembles
  • 3 choruses
  • 40th year participating in the ABC Music Festival 
  • 2 dance concerts a year with student-choreographed pieces



championships including dozens of state titles



  • 32 interscholastic sports teams (16 Upper School and 16 Middle School)
  • 20+ sports offered
  • 12 tennis courts
  • 8 athletic fields (football, soccer, baseball, field hockey, lacrosse, rugby, softball, and cricket) 
  • The new 87,000 square foot Simon Field House opened this year! 

Community and Student Leadership

School Houses

4 Upper School Houses
3 Middle School Houses
4 Lower School Houses

House Leadership Positions

32 Upper School leadership positions
6 Middle School leadership positions
14 Lower School leadership positions

Service Hours

100% of students participate in community service projects. Upper School students performed 4,475 hours of service from 2021-2022. More than $30,000 raised annually through donations for service/learning projects in South Africa and the Dominican Republic.

  • 30 Upper School House-sponsored activities
  • 1,130 of the 4,475 service hours during the 2021-2022 academic year were completed for senior projects

100% of Students

In Upper School, Middle School, and Lower School, all students receive a School-issued MacBook or iPad

Complete a senior capstone

In Upper School and Middle School, students travel domestically and/or internationally with Principia 

Participate in community-service activities

100% of Students:

  • Study the United Nations Sustainable Development Goals through independent projects in our annual Impact Challenge
  • Upper School seniors deliver a speech to the community 
  • Upper School students create multimedia presentations for classes
  • Middle School students engage in cross-curricular projects
  • Eighth graders give an end-of-year speech to the community


Plane planet

6,671 Upper School alumni live in 41 countries around the world

National Rankings and Recognitions


Best Christian High School
in Missouri


Best High School for the Arts
in Missouri


Best Private K–12 School
in St. Louis Area


Best Boarding High School
in Missouri

USDE Green Ribbon Schools 2022

Professional Accreditation, Affiliations, and Associations 

Principia Upper School is accredited by the Independent Schools Association of the Central States (ISACS). 

Just a few of our Affiliations and Associations:

  • National Association of Independent Schools (NAIS)

  • Independent Schools of St. Louis (ISSL)

  • Cum Laude Society

  • Missouri State High School Activities Association (MSHSAA)

  • National Association of College Admissions Counseling (NACAC) and Missouri Association of College Admissions Counseling (MOACAC)

  • American School Counselor Associations (ASCA) and Missouri School Counselor Associations (MSCA)

  • NWEA, formerly known as the Northwest Evaluation Association