<p>In Colorado, I’ve never heard of USAMO or USPhO. There are “MathCounts” contests (team and individual), but mostly done in the middle school (6th-8th grade) in our area. </p>
<p>If you are looking for a comparison factor beyond the normal SAT/GPA stats, post #4 about college courses is a good idea. Also AP courses (especially Calc BC) & IB courses (especially 2 yr “Higher Level” sequences - Math HL, Physics HL, Chemistry HL). Not all schools offer these courses, but the students who opt to take them are typically bright and motivated.</p>