===I am goign to build a pole barn. I need to extend the posts 6 inches
===below the frost line. How do I find out what the frost line is for my
===area?

I used to live in Kansas. Same latittude, frost line was three feet for
water lines.

If you think a severe thunderstrom might happen sometime in the life of the
barn, I'd go deeper than that. Poles hold your barn from blowing away.

Karl