Background: Prolonged field care (PFC) is field medical care applied beyond doctrinal planning time-lines. As current and future medical operations must include deliberate and contingency planning for such events, data are lacking to support efforts. A case review was conducted to define the epidemiology, environment, and operational factors that affect PFC outcomes. Methods: A survey distributed to US military medical providers solicited details of PFC encounters lasting more than 4 hours and included patient demographics, environmental descriptors, provider training, modes of transportation, injuries, mechanism of injury, vital signs, treatments, equipment and resources used, duration of PFC, and morbidity and mortality status on delivery to the next level of care. Descriptive statistics were used to analyze survey responses. Results: Surveys from 54 patients treated during 41 missions were analyzed. The PFC provider was on scene at time of injury or illness for 40.7% (22/54) of cases. The environment was described as remote or austere for 96.3% (52/54) of cases. Enemy activity or weather also contributed to need for PFC in 37.0% (20/54) of cases. Care was provided primarily outdoors (37.0%; 20/54) and in hardened nonmedical structures (37.0%; 20/54) with 42.6% (23/54) of cases managed in two or more locations or transport platforms. Teleconsultation was obtained in 14.8% (8/54) of cases. The prehospital time of care ranged from 4 to 120 hours (median 10 hours), and five (9.3%) patients died prior to transport to next level of care. Conclusion: PFC in the prehospital setting is a vital area of military medicine about which data are sparse. This review was a novel initial analysis of recent US military PFC experiences, with descriptive findings that should prove helpful for future efforts to include defining unique skillsets and capabilities needed to effectively respond to a variety of PFC contingencies.