What is elevation? 
If you cannot see the ocean from your classroom, you may not realize that your school could be hundreds to thousands of feet higher than the level of the ocean. The height of any place on land above sea level is called its elevation.

For example, the Ocean Drilling Program at Texas A&M University is in College Station, TX, which is at an average elevation of 367 feet above sea level.
Click here to find the source of this Texas elevation information. 
How is elevation calculated? What is sea level?
Let's Ask Yahoo! (Note: Look for the third paragraph of this page to find a quick answer.)