A contingent remainder is a subtype of a remainder, or a future interest in the grantee. Contingent remainders can come in two forms: a remainder is created in an unknown person or a remainder that has a condition precedent to possession. It is a future estate with some uncertainty - either in the identity of the possessor ("then to my children" leaves uncertainty as to how many children there will be) or if the person will actually take the estate ("to my son, unless he moves away").
Contingent remainders are non-vested, future interests of a grantee that are subject to the Rules Against Perpetuities. Contingent remainders have the capacity of becoming possessory at the expiration of the prior possessory estates, cannot divest the prior estates, and must immediately divest to the transferor. If the contingent remainder has a condition precedent to possession, the future interest must transfer immediately, with no gap of time, upon the natural termination of a prior estate once the condition precedent is met.
[Last updated in December of 2021 by the Wex Definitions Team]