Delaware Code Title 12. Decedents' Estates and Fiduciary Relations § 1302. Proving will

(a) A will shall be proved before the Register of Wills of the county in which the testator was domiciled at the time of death.  If the testator was not domiciled in this State, it may be proved before the Register of any county in this State wherein there are any goods or chattels, rights or credits, or lands or tenements of the deceased.

(b) To be effective to prove a transfer of any property or to nominate an executor, a will must be declared to be valid by admission to probate.