http://gauss.usouthal.edu/~mathcircle/
http://ime.math.arizona.edu/tmc/index.html
http://mathcircle.berkeley.edu/
http://bact.mathcircles.org/
http://mathteacherscircle.org/
http://explore.math.ucdavis.edu/
http://www.math.uci.edu/~mathcirc/
http://www.csulb.edu/depts/math/arml/index.htm
http://www.math.ucla.edu/~radko/circles/
http://oebmc.mathcircles.org
http://philo.exploratorium.edu/~jcarter/omc.htm
http://www.avidacademy.com/
http://www.sdmathcircle.org/
http://www.sfmathcircle.org
http://www.sanjosemathcircle.org
http://www.stanfordmathcircle.org
http://www.marinmathcircle.org
http://familyrun.ning.com/profiles/blogs/math-salon
http://ccms.claremont.edu/GEMS
http://www.math.ucsb.edu/mathcircle/
http://www.coloradomath.org
http://www.uccs.edu/~pipes/ppmtc.html
http://home.gwu.edu/~dullman/dcmc/index.html
http://www.flsam.tk/
http://mathcircles.fiu.edu/
http://atlanta.aiuniv.edu/
http://www.math.iastate.edu/CIMSMTC/circle.html
http://riverbendmath.org/calendar/
http://mlarsen.math.indiana.edu/~larsen/MathCircle.html
http://rsmlouisville.com
http://www.themathcircle.org/
http://www.stmarksschool.org/academics/mathinstitute.aspx
http://www.girlsangle.org/
www.artofinquiry.net
http://flintmathcircle.kettering.edu/
http://www.math.msu.edu/~mshapiro/KidMath/KidMath.html
http://www.dehn.wustl.edu/~blake/circles/
http://www.metamo4icmathcenter.com/index.html
http://www.math.uncc.edu/~hbreiter/TeachersCircle/index.htm
http://www.davidson.edu/math/cmc/
http://www.naturalmath.com
http://www.math.ncsu.edu/MathCircles
http://www.nebrwesleyan.edu/people/cminer/teachercircle.html
http://www.princetonmathcircle.org/
http://albanyareamathcircle.blogspot.com/
http://giftedmath.buffalo.edu/
http://comet.lehman.cuny.edu/mathcircle/
http://www.nymathcircle.org/
http://www.metroplexmathcircle.org
http://www.ma.utexas.edu/users/smmg/
http://www.math.tamu.edu/outreach/BVMTC/
http://www.midcitiesmathcircle.org
http://www.math.byu.edu/~wright/Math%20Circle/BYU_MathCircle.html
http://www.math.utah.edu/mathcircle/
http://www.math.utah.edu/teacherscircle/
http://groups.google.com/group/fairfax-math-circle
http://simathcircle.org/default.aspx
http://assagames.com/nas/MathCircle.html
http://uwacadweb.uwyo.edu/UW_MATH_CIRCLE/