Achieving clear margins during surgical resection in oral cavity squamous cell carcinoma (OCSCC) is thought to reduce local recurrence (LR) and improve prognosis; however, what constitutes a clear, close, or involved margin is inconsistent in the literature and in practice. Most commonly, a margin of less than 5mm has been considered close, however, this determination appears to have been arbitrary and has persisted despite a lack of supporting evidence. A review of articles that report outcomes specifically for patients with close margins demonstrates a broad range of local recurrence rates, from 6% to 74%, but these have generally placed patients with margins of less than 5 mm into one group and have not considered individual margin distances. In this study, authors have sought to gain clarity on what should be considered a clinically significant close margin. Local recurrence (LR) rate for microscopic positive margins was 44%; for margins less than 1mm, 28%; for 1mm, 17%; for 2mm, 13%; for 3mm, 13%; for 4mm, 14%; and for 5mm or greater, 11%. This retrospective analysis of a series of patients with OCSCC treated with surgery demonstrates that the risk of LR increases rapidly with less than a 1mm distance from the cut tissue edge and such patients may benefit from additional treatment.