Terrain in distance is blue and foggy

Our terrain (which is roughly 5 sq km) in the distance starts out blue and foggy. Here is a picture of the terrain:

http://puu.sh/3KPnY.jpg

We would like to know how to eliminate it, or even tone it down so that it doesn’t look so overpowering.

You probably have fog checked under the render settings. There are some settings there you can adjust if you decide you want to keep the fog, or you can just turn it off altogether.