I'm researching United State zip codes and elevation. Specifically high schools elevations in US.
You can get the US Department of Education's list of all public/private schools here:
This data contains the type of school (e.g., High School) along with the latitude and longitude coordinates.
There are a number of services on the Internet that offer elevation data based on coordinates. I have not used any, so I can't make a recommendation. I would google something like 'elevation by coordinates'