I was paid out for the termination of a trust fund from my Grandmother's estate when my father passed. Do I have to include this as income on my tax return?

"Do I have to include this as income on my tax return?"

That depends and the only way to know for certain is to (a) contact the trustee immediately or (b) wait and see if you receive a tax reporting statement (in this instance a Schedule K-1, which will contain any items of income, deductions, gains, and/or credits that need to be reported on your individual income tax return).