Its an adjustment on the state return, what state is it?  I can point you to the line if its California.

Thanks, it's Illinois. The instructions I've found said to enter on Schedule M, Line 22 but in order to do so, I have to do an override. Therefore, I am thinking that there may be a spot elsewhere to put it, but I can't find it.

Im not familiar with IL, sorry

Enter it in the same place you would if you got a 1099-INT for interest on US Obligations.

Since it's a Grantor Trust, you should have put the interest income on federal Sch B, just the same as you would have if you got the 1099INT from the bank. 

Enter US Bond interest on Sch B.

That's what I did but it doesn't automatically transfer over to the state as a deduction. It appears I can only enter it by overriding in the state.

did you check that the total interest shown on the state is the same as total interest on the federal? maybe it is less and you don't see it on a separate line. 

It works for me. I entered $100 as regular interest and $1,000 as US bond interest on Sch B.

On IL Sch M line 22 it is a subtraction of $1,000.