D.C. Mun. Regs. tit. 9, r. 9-3703
The taxable situs of real property shall be the place where the real property is situated.
Real property having an actual situs outside the District shall not be taxable with respect to a resident decedent where the property is held in a personal trust.
Real property having an actual situs in the District shall be taxable with respect to a nonresident decedent, including property held in a personal trust.
All other indirect interests in real estate (e.g., partnership, corporate) shall for District estate tax purposes be regarded as intangible personal property.
A contract to convey land shall constitute an equitable conversion so that the seller's interest is personal property and the buyer's interest is real property.
The taxable situs of tangible personal property shall be the place where the property is customarily located at the time of the decedent's death.
The taxable situs of tangible personal property which, by its nature, is readily movable shall be determined by the Deputy Chief Financial Officer from the facts of each case.
If readily movable tangible personal property belonging to a decedent domiciled within the District is accidentally or casually outside of the District at the time of the decedent's death, the taxable situs of that property shall be the District.
The taxable situs of intangible personal property other than business use intangible personal property shall be the domicile of the decedent at the time of the decedent's death.
The taxable situs of business use intangible personal property as defined in § 3799.2 shall be in the District, regardless of the resident of the decedent.
D.C. Mun. Regs. tit. 9, r. 9-3703