Clipping distance?

I can’t figure this out for some reason… I’ve gotten pretty far into OpenGL and haven’t hardly bothered with it, but there seems to be a very low clipping distance (as in when an object gets too far away, it starts loosing many triangles). I can help this with fog, but I want to push it back, not just make it look nice. Thanks for any help!

what function do you use to set the clipping planes?
glOrtho() or what???