The Southern California region is both a known ecological hotspot and an area with a large and increasing human population. To address species conservation and maintain habitat connectivity in this heavily populated area, numerous habitat conservation plans, natural community conservation plans, and regional plans have been developed that identify conservation areas and wildlife corridors. Due to their linear footprint and constraints from adjacent development, transportation corridors cross many conservation areas and wildlife corridors. Early coordination in the transportation project development process is crucial to the maintenance of wildlife connectivity in the Southern California region. Monitoring during and after project construction is necessary to ensure that wildlife crossing features are implemented and function as planned. We provide examples of efforts to maintain wildlife connectivity across transportation corridors from the fine scale of the individual crossing to the broader context of existing large-scale regional plans.