USA Nationwide:
National Association of Independent Schools: http://www.nais.org
General Directory / Boarding Schools: http://www.schools.com/schoolsearch.html
General Directory / Junior Boarding Schools: http://www.jrboarding.org

States / Regions:
New England states except Connecticut: http://www.aisne.org
Independent Schools Association of the Central States: http://www.isacs.org
Connecticut: http://www.caisct.org
GHAISA (Greater Hartford Area Independent School Association): http://www.dgne.com/schools
Chicago area: http://www.cais.org
Florida: http://www.st.pauls.edu/FCIS/FCIS_HP.html
Georgia: http://www.mindspring.com/~gisa/gisa2
Maryland: http://www.aimsmd.org
New York: http://www.nysais.org
Oregon: http://www.prsnet.com/prsnet/ofis/ofis.html
Pacific Northwest Association of Independent Schools: http://www.pnais.org

Types of Schools (U.S.A.):
Sacred Heart Schools: http://www.mcs.net/~sophie/

Outside the U.S.A.:
Canada (Ontario): http://www.xe.net/isnet/
United Kingdom: http://www.schools-directory.co.uk/
Round Square: http://www.lakefieldcs.on.ca/roundsquare/
The Round Square Conference is an international group of Schools based upon the educational principles of the late Dr. Kurt Hahn and drawn from Africa, Australia, Canada, Germany, India, Switzerland, UK and USA.

Other Organizations:
CCY (Center for Creative Youth): http://www.crec.org/ccy
The Center for Creative Youth's mission is to provide quality arts education in a pre-college setting in order to prepare students for success in future education and careers.