What is Lex Rei Sitae?

Legal Definition
Lex rei sitae is a legal doctrine of property law and of International private law. It is Latin for "the law where the property is situated". The law governing the transfer of title to property is dependent upon, and varies with, the lex rei sitae.
-- Wikipedia
Legal Definition
The law of the place where the thing is situated. See 136 Pa. St. 354, 20 Am. St. Rep. 925, 11 L. R. A. 85, 20 Atl. 521.
-- Ballentine's Law Dictionary
Legal Definition
The law of the place of situation of the thing.
-- Black's Law Dictionary