Background: The optimal use and sequence of radiation therapy (RT), chemotherapy, and surgery for patients with stage III non-small cell lung cancer (NSCLC) is unknown. We conducted a cross-sectional study using the Surveillance Epidemiology and End Results (SEER) population-based cancer registry to examine the relationship between year of diagnosis and receipt of neoadjuvant RT for patients with stage III NSCLC diagnosed in the United States from 2000 to 2008, with additional focus on the role of race and treatment location. Methods: Thirteen SEER registries were used for data analysis. Patients diagnosed with stage III NSCLC treated with both surgery and RT between the years 2000 and 2008 were included. We used multiple logistic regression to describe the relationship between type of therapy for lung cancer and year of diagnosis. Covariates identified for analysis included age, grade, sex, race, ethnicity, and SEER registry. Results: The total sample size was 393,711 of which 5,949 patients met our inclusion criteria. The cohort had a mean age of 64, was predominantly white (85.8%) and had predominantly high grade tumors (50.9%). Use of neoadjuvant RT for stage III NSCLC was lowest in 2000 and higher in every year from 2002 to 2008 (OR 1.325 in 2002, p= 0.035; 1.921 in 2007, p<0.0001). Substantial heterogeneity among registries existed, with more neoadjuvant RT use in Seattle and San Francisco-Oakland (OR 1.83, 1.698 p<0.0001 and 0.0002 respectively) and less use in Metropolitan Detroit, New Jersey and Louisiana (OR 0.754, 0.570, 0.493, p=0.25, <0.0001, and <0.0001 respectively). Black race was significantly associated with lack of neoadjuvant therapy without controlling for registry, but the association weakened after controlling for registry (OR 0.81, p=0.072). Conclusions: The use of neoadjuvant RT for stage III NSCLC substantially increased from 2000 to 2008. Location of treatment was strongly associated with receipt of neoadjuvant therapy and outweighed the association of race and therapy. The effort to equitably distribute care should focus additional study on the important role of regional and local medical culture in determination of medical care.