Since my 2019 return, I have closed my account that my refund was issued to, and I did move out of state (thus changing my address). Where will the stimulus check go?

Well---you have outdated information on record with the IRS.   If the deposit goes to a closed account it will bounce back to the IRS.  Then the IRS will mail a check---but you have changed addresses.  Some post offices will forward govenment mail--and some will not.  Hope you have a mail forwarding form in place.

When you prepare your 2020 tax return you can change your address in My Info--but that will not go to the IRS until you file your tax return.  The IRS will not be accepting 2020 returns until the end of January.

To change your address now with the IRS  --- but this takes weeks --

CHANGE OF ADDRESS

https://www.irs.gov/faqs/irs-procedures/address-changes/address-changes

Make sure the post office is forwarding your mail.

From the IRS

My address has changed or is incorrect. What can I do to change or correct it to receive my Payment? (updated December 8, 2020)

Get My Payment won't allow you to change your address. If you need to change your address, see Address changes.