According to the National Center for Education Statistics, there were approximately 171,400 students enrolled in junior high schools (grades 7-8) in Nassau and Suffolk counties on Long Island in the 2020-2021 school year.
Senior High School Population in Long Island
In the same school year, there were approximately 185,700 students enrolled in senior high schools (grades 9-12) in Nassau and Suffolk counties.
It's important to note that these numbers may have changed since the 2020-2021 school year, as enrollment levels can fluctuate from year to year. For the most up-to-date information, I recommend checking with the New York State Education Department or the individual school districts on Long Island.