Different mechanisms can cause bone fractures. This retrospective study considers whether the distribution of cranial fractures can help distinguish the mechanism by which fractures formed. Data are from two sources: cases of motor vehicle collision (MVC) and fire-related deaths obtained from the Jefferson County Coroner/Medical Examiner (JCC/MEO) archives and information on fatal MVCs from the National Automotive Sampling System Crashworthiness Data System (NASS/CDS). In review of the JCC/MEO archives, cranial fractures were documented in 30% of MVC deaths. Fractures were restricted to the base of the skull in 45% of those cases, involved both base and cranial vault in 53%, and was confined to the cranial vault in 2.6%. Cranial fractures were documented in only 4% of deaths involving fire. The NASS/CDS data (n=31 911) are similar, with fracture involving only the base of the skull in 40.9% of cases, both base and vault in 42.3% of cases, and vault only in 16.8% of cases. Cranial fractures in fire-related MVCs vs. non-fire MVCs were more likely to involve the vault only (31.5% vs. 16.9%) and less likely to involve the base and vault (36.4% vs. 45.0%) or base only (32.1% vs. 38.1%). In conclusion, most (>90%) cranial fractures related to MVCs involved the base of the skull. Few deaths only associated with fire were associated with cranial fracture (4%). In circumstances where alternate mechanisms for fracture exist, such as a vehicle catching fire after a collision, fracture of the base of the skull supports the collision as the likely mechanism of fracture.