Background: Large population-based studies on TNBC epidemiology and treatment pattern in the US were generally limited due to lack of routinely data collection on these biomarkers until recent years. This study examined and documented general treatment status and factors associated with the treatments among TNBC patients in the US. Methods: We used the latest released NPCR and SEER combined cancer registry data, which covers 100% of the US population. All women in the US with a primary invasive TNBC breast cancer diagnosed between 2013 and 2015 were included. First course treatment patterns by AJCC staging on TNBC were examined based on corresponding year’s NCCN guideline recommendations. Regression analysis were performed to identify factors associated with treatments. Results: There were 74,952 TNBC women included in the study. Ninety three percent of women with early stage of TNBC had surgery, and 35% women with mastectomy chose to undergo contralateral prophylactic mastectomy. Among stage I-III patients, those aged < 35, Non-Hispanic Asian Pacific Islander, living in other regions than northeast or metropolitan were more likely to have mastectomy compared to BCS. Radiation therapy were only received for 65% women with breast conserving surgery (BCS), which were less likely to be performed in non-Hispanic Black, Hispanic, and among those aged < 35 or > 70+. Chemotherapy were received for 75% of TNBC women, ranged from 63% (stage I) to 86% (stage III). Treatment variations among different demographic and geographic characteristics in chemotherapy were also observed. Conclusions: Overall, current treatment practice for TNBC in the US is generally concordance with the recommended breast cancer care except a relative low radiation therapy among BCS women. However, treatment disparities existed within the limited treatment options, and factors associated with the disparities also varied. More effective treatment options and treatment equality are warranted to improve overall care of this subtype.