20 CFR 416.216: You are a child of armed forces personnel living overseas.

(a) General rule. For purposes of this part, overseas means any location outside the United States as defined in § 416.215; i.e., the 50 States, the District of Columbia and the Northern Mariana Islands. You may be eligible for SSI benefits if you live overseas and if—

(1) You are a child as described in § 416.1856;

(2) You are a citizen of the United States; and

(3) You are living with a parent as described in § 416.1881 who is a member of the armed forces of the United States assigned to permanent duty ashore overseas.

(b) Living with. You are considered to be living with your parent who is a member of the armed forces if—

(1) You physically live with the parent who is a member of the armed forces overseas; or

(2) You are not living in the same household as the military parent but your presence overseas is due to his or her permanent duty assignment.