Background: Unlike children with acute lymphoblastic leukemia (ALL) who receive cancer care almost exclusively from pediatric oncologists at specialized cancer centers (SCC; defined here as National Cancer Institute and/or Children’s Oncology Group designated cancer centers), adolescents and young adults (AYAs; 15-39 years) in the United States receive care in a variety of settings. Using state-wide population-based data, we sought to describe the health care delivery settings in which AYAs with ALL receive treatment and determine associations between front-line treatment at an SCC and leukemia-specific and overall survival (LSS/OS). Methods: We used data from the 2004-2018 California (CA), New York (NY), and Texas (TX) state cancer registries to identify front-line treatment setting of AYAs newly diagnosed with ALL. Multivariable logistic regression models evaluated characteristics associated with receiving treatment at an SCC. Cox proportional hazards regression models evaluated the associations with LSS/OS. All models were adjusted for gender, age, sex, race/ethnicity, socioeconomic status, insurance, and diagnosis year. Results: The cohort was comprised of 2283 (CA), 795 (NY), and 955 (TX) AYAs with ALL. Across all states, approximately 70% were ³18 years and 65% were male. Race/ethnicity varied by state: a majority in CA (63%) and TX (64%) were Hispanic, while most in NY were non-Hispanic White (NHW) (50%). Health insurance coverage also varied: most in CA were publicly insured (48%), while most in NY were privately insured (54%); TX had the highest rate of uninsured (18%). Treatment at an SCC occurred in 48.2% (CA), 44.4% (NY), and 19.5% (TX) of AYAs, increasing in CA and NY over time, but remaining unchanged in TX. Among all states, older age and uninsured status were significantly associated with lower odds of treatment at an SCC. In both CA (OR 0.58, 95% CI 0.45-0.74) and TX (OR 0.55, 95% CI 0.35-0.86), Hispanic patients had significantly lower odds of treatment at an SCC than NHW. In NY (OR 0.45, 95% CI 0.31-0.67) and TX (OR 0.49, 95% CI 0.3-0.8), publicly insured AYAs had significantly lower odds of receiving treatment at an SCC than those with private insurance. Front-line treatment at an SCC was significantly associated with both superior LSS (HR 0.73, 95% CI 0.63-0.85) and OS (HR 0.73, 95% CI 0.63-0.85) in CA and superior LSS (HR 0.70, 95% CI 0.51-0.94) and OS (HR 0.61, 95% CI 0.45-0.83) in TX; a non-significant association was seen in NY (LSS: HR 0.86, 95% CI 0.65-1.12; OS: HR 0.83, 95% CI .64-1.08). Conclusions: Only 20-50% of newly diagnosed AYA ALL patients receive front-line treatment at SCCs, with age, race/ethnicity, and insurance type independently influencing AYA ALL care setting. We show that the treatment of ALL at an SCC is associated with superior survival, highlighting the importance of statewide and national policy efforts to improve access and reduce inequities in AYA ALL.