Background: In this nationwide population-based cohort study, we investigated the overall minimum margin width that is independently associated with improved survival following pancreaticoduodenectomy (PD) for pancreatic ductal adenocarcinoma (PDAC) and evaluated whether certain margins or surfaces hold independent prognostic significance. Methods: Data from 367 patients who underwent PD for PDAC in the period 2015–2019 were retrieved from the Danish Pancreatic Cancer Database. Missing data were obtained by review of pathology reports and re-microscopy of resection specimens. Surgical specimens were evaluated using a standardised pathological protocol involving multicolour inking, axial slicing and exact reporting of circumferential margin clearances in 0.5 mm increments. Results: When categorised according to margin widths of <0.5, <1.0, <1.5, <2.0, <2.5 and <3.0 mm, R1 resections were detected in 34%, 57%, 75%, 78%, 86% and 87% of cases, respectively. In multivariable analyses, an overall margin clearance of ≥1.5 mm was associated with improved survival compared with a clearance of <1.5 mm (HR 0.70 95% CI 0.51–0.97 (p = 0.031)). When evaluating the margins separately, no margin had independent prognostic significance. Conclusion: Margin clearance of at least 1.5 mm was independently associated with improved survival following PD for PDAC.