Some 2.8 million Americans seek medical attention for traumatic brain injury (TBI) annually, resulting in estimated annual costs of over $75 billion. Older adults have the highest and fastest rising rate of TBI of any other age-group, with 1 in 50 adults age ≥75y seeking medical attention for TBI in 2013. Older adults with TBI experience higher mortality, slower recovery, worse outcomes, and may be at especially high risk for post-TBI dementia. There are few evidence-based guidelines for management, no tools to provide patients and families with reliable estimates of prognosis, and few proven treatments. Progress has been limited by: 1. Systematic exclusion of older disabled patients from most prior prospective TBI studies, and 2. lack of age-appropriate TBI research tools. The overall objective of TRACK-TBI GERI is to launch a 2-site prospective geriatric TBI cohort study that will directly address these barriers by applying state-of-the-art geriatric research methods to the field of TBI to improve representation of older patients in TBI research, and to develop a novel approach to measuring age appropriate TBI predictors, outcomes, blood-based biomarkers, and neuropathology.