Prognostic risk factors for pediatric brain tumors were examined using a U.S. SEER population-based cohort of 15,723 pediatric brain tumor patients, diagnosed and followed between 1975-2016. Stratified Cox Proportional Hazards models were used for all analyses. Mortality risk declined with increased age at diagnosis, the adjusted hazard ratio (aHR) (95% Confidence Interval) was 0.60 (0.55, 0.67) and 0.47 (0.42, 0.52) for 1-10 years and 10-19 years, respectively, when compared with infants. Caucasian patients had a lower risk of mortality than African Americans (1.21 (1.11, 1.32)). Primary tumor sites, grades, and histology showed substantial heterogeneity in mortality risk. Brainstem (2.62 (2.41, 2.85)) and Cerebrum (1.63 (1.46, 1.81)) had an elevated risk of mortality compared to lobes. Compared to low-grade glioma, high-grade glioma (7.92 (7.09, 8.85)), Primitive neuroectodermal tumors (4.72 (4.15, 5.37)), and Medulloblastoma (3.11 (2.79, 3.47)) had increased risk of mortality. County-level poverty and geographic region showed substantial variation in survival. This large study provided estimates of prognostic risk factors, with high generalizability, using 4 decades of data.