<p>Suicide remains a leading cause of death among young adults in the USA, yet many who experience suicidal ideation do not receive treatment. Guided by the Healthy People 2030 framework, this study examined how social determinants of health (SDOH) are associated with past-year suicidal ideation and mental health treatment utilization among young adults aged 18–25. Using 2022 NSDUH data (<i>N</i> = 13,739), we estimated two complex samples logistic regression models. Suicidal ideation was more likely among individuals with less education, rural residence, housing instability, exposure to community drug activity, and infrequent religious service attendance. Among those with ideation, treatment was more likely among respondents who were insured, college educated, and reported greater impairment and less likely among those who were unemployed or exposed to community drug activity. Findings underscore the influence of structural and community-level conditions on suicide risk and mental health care utilization in this vulnerable population.</p>