Mine was ~1200 and I thought that was a lot, I live in a big city.
It had 3000 at one point before I went, but the number drops every year. It had 3 floors, and by Grade 12 all the lockers on the first floor were bolted and were not used anymore.
Yeah, in the US there are like 36 students in a classroom. In total, I think the average is somewhere around 3,000 kids. I went to 2 different high schools, one in Canada and one here in the US. At my first school there were like 400-500 kids at the most, probably a lot less. The school I attended in the US was highly selective enrollment & it had about 800 kids. Possibly up to 900 but I don't think 1,000. The acceptance rate was disgustingly low.