Purpose: The influence of tumor location on survival was investigated in patients with lung cancer who received radical chemoradiotherapy. Methods: We examined the relationships between radiation site and survival outcome in patients with lung cancer. A total of 14,640 patients with lung cancer who received radical chemoradiotherapy for stage I-III disease were reviewed from Surveillance, Epidemiology, and End Results Program (SEER) datasets. We further retrospectively collected cases from a cohort of 148 eligible patients diagnosed between December 2013 and December 2019. Results: Female sex, adenocarcinoma, and stage III disease were significantly correlated with right lung lobe tumor. Advanced age at diagnosis was associated with lower lung tumor origin. For the patients who received radical chemoradiotherapy, 1- and 3-year survival rates were 56.5% and 22.9%. Lower lobe origin was closely related to a shorter overall survival compared to non-right lower lobe tumors (p < 0.001). We also validated the difference in our cohort (p = 0.004). Conclusions: Our results suggest that lower lobe tumor increases mortality risk in patients with lung cancer treated with radical chemoradiotherapy.