Question
               You asked us to consider the effect of a divorced spouse’s opposite-sex civil union
                  in Illinois on her entitlement to divorced spouse’s benefits on her former spouse’s
                  earnings record.
               
               Short Answer
               For the reasons stated below, we believe that the opposite-sex civil union in Illinois
                  constitutes a “marriage” for benefits purposes and renders the divorced spouse ineligible
                  to receive benefits on her former spouse’s earnings record.
               
               Background
               D~ legally married P~ on September X, 1977, in C, Illinois. They divorced on March
                  XX, 2001, in Illinois.
               
               D~ subsequently entered into a civil union with L~ on January XX, 2017, in Waukegan,
                  Illinois. The couple continues to live in Illinois.
               
               D~ filed an application for divorced spouse’s benefits on P~ earnings record on August
                  XX, 2018. On her application, she alleged that she was not currently married. You
                  have asked whether the agency should consider D~, following her civil union, “married”
                  for benefits purposes and therefore not entitled to divorced spouse’s benefits.
               
               DISCUSSION
               Under the Social Security Act (Act), a divorced wife may be entitled to benefits on
                  the record of her former spouse if she meets certain requirements. 42 U.S.C. § 402(b).
                  She must (A) file an application for wife’s insurance benefits; (B) have reached age
                  62; (C) not be married; and (D) not be entitled to old-age or disability benefits
                  based on a primary insurance amount that is equal to or greater than the full wife’s
                  benefit. Id.;see alsoid.
                     § 416(d)(1) (defining “divorced wife” as a woman who was married to an individual
                  for 10 years immediately before the divorce became final); 20 C.F.R. § 404.331 (also
                  requiring a divorced wife to have been divorced from the insured for at least 2 years).
                  The issue in this case is whether D~ is “not married,” as required by 42 U.S.C. §
                  402(b)(1)(C), in light of her civil union with L~ after her divorce from P~.
               
               We look to state law to determine whether a divorced wife was validly married to her
                  former spouse. 42 U.S.C. § 416(h)(1)(A); 20 C.F.R. §§ 404.331(a)(1), 404.345 . The
                  validity of their marriage is determined by applying the law of the state in which
                  the former spouse was domiciled. 42 U.S.C. § 416(h)(1)(A)(i); 20 C.F.R. §§ 404.331(a)(1),
                  404.345. However, neither the Act nor the regulations address which law governs the
                  validity of the divorced wife’s remarriage to a third party. Here, we believe that
                  the law of Illinois should be applied because the civil union between D~ and L~ occurred
                  in Illinois, and they continue to live in that state.
               
               The Illinois Religious Freedom Protection and Civil Union Act (Civil Union Act), which
                  went into effect in June 2011, permits a civil union between two persons of either
                  the same or opposite sex. 750 Ill. Comp. Stat. 75/1. The Civil Union Act makes clear
                  that a civil union is equivalent to a marriage under Illinois law. For example, it
                  states that a “party to a civil union” means and is included in any definition or
                  use of the terms “spouse,” “family,” and other terms that denote the spousal relationship.
                  Id. 75/10. Moreover, the Civil Union Act specifically provides that “[a] party to a civil
                  union is entitled to the same legal obligations, responsibilities, protections, and
                  benefits as are afforded or recognized by the law of Illinois to spouses.” Id. 75/20.
               
               Here, the evidence includes a Certification of Civil Union issued by L County, Illinois,
                  showing that D~ and L~ entered into a civil union in January 2017. As discussed above,
                  their civil union is equivalent to a marriage in Illinois. There is no evidence that
                  D~ and L~ dissolved their civil union. Consequently, we consider D~ “married” for
                  purposes of entitlement to divorced spouse’s benefits on her former spouse’s earnings
                  record.
               
               CONCLUSION
               For the reasons discussed above, we conclude that D~ is currently “married” based
                  on her civil union with L~, and thus she is not eligible to receive divorced wife’s
                  benefits on P~ earnings record.