A message came from the American Mathematical Society - the winner of the American Mathematical Olympiad was the Georgian-American high school.
According to the Georgian-American High School, the contestants were 40 high school students from 15 US states. (Alabama, Connecticut, Indiana, Kentucky, Maine, Massachusetts, Michigan, Mississippi, New Hampshire, New Jersey, New York, Ohio, Rhode Island, Tennessee, and Vermont)
The Olympiad is held in three rounds in December, January, and February. Each round consists of 15 tasks.
The top ten winners of 2017-2018 look like this:
Georgian-American High School
Vestavia Hills High School
Alabama School of Fine Arts
William G. Enloe High School
Farragut High School
Kentucky Country Day School
Spain Park High School
Ridge High School
William Mason High School
Revere High School
For this victory, the Georgian-American high school will be awarded a special prize from the American Mathematical Union.