St. Louis MathMath Circles
- MathCircles.org - National Association of Math Circles
- Prime Factor Math Circle
- Berkeley Math Circle
- San Jose Math Circle
- Stanford Math Circle
- Utah Math Circle
- Marin Math Circle
- The Math Circle Boston
- Mobile Math Circle Alabama
- San Diego Math Circle
- Florida International University Math Circle
- Lehman College Math Circle
- Texas Saturday Morning Math Group
- Grant Park High School Math Circle
- NW Academy of Sciences Circle
- Talking Stick Learning Center
- UCLA Math Circle
- Waterloo Math Circle
- Julia Robinson Mathematics Festival
- Art of Problem Solving: Summer Program List
- AMS Summer Camp List
- MEGSSS (St. Louis)
- Kevin Hopkin's Math Camp (Bolivar, MO)
- Euclid Lab
- Awesome Math
- MathPath
- Jacobs University Summer School (Europe)
- Math Competition List (Art of Problem Solving)
- Math Kangaroo
- Florissant Valley Excellence in Math (MO)
- MCTM Math Contests (MO)
- AMC: American Math Competitions
- IMO: International Mathmatical Olympiad
- Math Counts
- Tom Davis' Geometer.org
- James Tanton (Thinking Mathematics)
- Math Alive
- Gregory Budzban's Problems
- Paul Doherty's Science and Math Explorations
- Harold Reiter's Page
- Missouri State Univeristy - Problem Corner
- Ken Duisenberg's Puzzle of the Week
- Mathematical Card Tricks
- Math Central Monthly Problem
- Cut the Knot
- Harvey Mudd Math Fun Facts
- CS Unplugged
- MathPuzzle.com
- George Hart (Bagels and Zomes)
- NRich Mathematics
- Whole Movement - Circle Folding
- Set Homepage
- Mathematische Bastenlein (great worksheet for Math Circles!)
- History of Math Problems
- Center for Innovation in Mathematics Teaching
- Natural Math Blog
- Math Research Project Ideas - TC Wu
- Linquistics Puzzles
- Brilliant