The prevalence of atrial fibrillation (AF) is increasing in the United States as the population ages, but national surveillance is lacking. This cross-sectional study (2006 to 2014) analyzed data from the Healthcare Cost and Utilization Project's Nationwide Emergency Department Sample, the National (Nationwide) Inpatient Sample, and the National Vital Statistics System. Event totals were estimated independently for emergency department (ED) visits, hospitalizations, and mortality, and then collectively after applying criteria to identify mutually exclusive events. Rates were calculated for AF as primary diagnosis or underlying cause of death (primary AF), as well as secondary diagnosis or contributing cause of death (co-morbid AF), and standardized by age to the 2010 US population. From 2006 to 2014, event rates increased for primary AF (249 to 268 per 100,000) and co-morbid AF (1,473 to 1,835 per 100,000). In 2014, an estimated 599,790 ED visits, 453,060 hospitalizations, and 21,712 deaths listed AF as primary. A total of 684,470 mutually exclusive primary AF and 4,695,997 mutually exclusive co-morbid AF events occurred. Among ED visits and hospitalizations with primary AF, the most common secondary diagnoses were hypertension, heart failure, ischemic heart disease, and diabetes. The mean cost per hospitalization with primary AF was $8,819. Mean costs were higher for those with co-morbid AF versus those without co-morbid AF among hospitalizations with a primary diagnosis of ischemic heart disease, heart failure, stroke, hypertension, or diabetes (all p ≤0.01). In conclusion, with the substantial health and economic impact of AF and an aging US population, improved diagnosis, prevention, management, and surveillance of AF are increasingly important.