Mapping Jewish High Schools in North America

Hart Levine recently posted the following on JEDLAB:
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For anyone who's ever been curious, I made a map of every (non-chassidish/yeshivish) Jewish high school in North America, including the size of their graduating 12th grade class (as of 2014). In total, it's 4,257 students in 96 schools!

[tinyurl.com]
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I found the map to be fascinating. My question is: What can we learn from this visual presentation?

Shalom