Child marriage, defined as marriage before 18 years old, continues to be legal with judicial and parental consent and practiced in 49 states in the United States (U.S.). Worldwide, child marriage results in negative socioeconomic and health outcomes for women. This study examined multiple variables associated with those who were married under 18 years old in the U.S. This study analyzed data from the National Survey of Family Growth from 2011 to 2015. Child marriage was defined as the respondents’ first marriage occurring before 18 years old. The control group was women whose first marriage occurred ≥ 18 years old. Bivariate and multivariable analyses were used to compare sociodemographic factors, parental factors, and health variables between women with and without history of child marriage. Almost 6% of women who had been married at least once were married before 18 years old. In bivariate analyses, women with a history of child marriage were more likely to be Latino (42% of child marriage group vs 17% of control group, p < 0.01), be born outside of the U.S. (30% vs 20%, p < 0.01), have a lower income (100-199% of poverty level vs 200-299% of poverty level, p < 0.01), have a mother who had her first child before 18 years old (31% vs 15%, p < 0.01), be forced to have vaginal sex (25% vs 14%, p < 0.01), believe that marriage has not worked out for most people they know (51% vs 31%, p < 0.01), and believe that divorce is the best solution when a couple cannot work out marital problems (53% vs 33%, p < 0.01). Women with a history of child marriage were less likely to have had an intact family until 18 years old (51% of child marriage group vs 63% of control group, p < 0.01), have a usual place to go for health advice (80% vs 89%, p < 0.01), report having excellent health (22% vs 29%, p < 0.01), and believe that same sex couples should have the right to adopt children (61% vs 73%, p < 0.01). In multivariable analysis, compared with white women, Latino women had double the odds of marrying before 18 years old. Living in the South and having ≤ 9th grade education was associated with double the odds of marrying before 18 years old. Older age at first sexual intercourse and being African American was associated with lower odds of being married before 18 years old. Child marriage in the U.S. is more common among Latino women and women living in the South, and less common in African Americans. Child marriage in the U.S. is associated with lower education, and increased likelihood to ever have been forced to have sexual intercourse. Future research should analyze why child marriage is more common among these populations, as prevention of child marriage may improve outcomes for women.