A civil union is a legally recognized relationship between members of a same-sex couple, with rights similar to those of a marriage relationship.
As of my knowledge cutoff in 2023, Idaho does not recognize civil unions. The state has a constitutional amendment that defines marriage as a union between one man and one woman, effectively prohibiting same-sex marriages and any legal recognition of same-sex relationships that resemble marriage, such as civil unions. This amendment was passed in 2006. However, the U.S. Supreme Court's decision in Obergefell v. Hodges (2015) legalized same-sex marriage nationwide, which means that same-sex couples in Idaho can marry and have their marriages recognized with the same rights and responsibilities as opposite-sex marriages. Despite this, there is no specific provision for civil unions in Idaho law, and same-sex couples seeking legal recognition of their relationship would typically pursue marriage rather than a civil union.