Injury to the CNS leads to formation of scar tissue,which is important in sealing the lesion and inhibiting axon regeneration. The fibrotic scar that comprises a dense extracellular matrix is thought to originate from meningeal cells surrounding the CNS. However,using transgenic mice,we demonstrate that perivascular collagen1a1 cells are the main source of the cellular composition of the fibrotic scar after contusive spinal cord injury in which the dura remains intact. Using genetic lineage tracing,light sheet fluorescent microscopy,and antigenic profiling,we identify collagen1a1 cells as perivascular fibroblasts that are distinct from pericytes. Our results identify collagen1a1 cells as a novel source of the fibrotic scar after spinal cord injury and shift the focus from the meninges to the vasculature during scar formation.