•We analyzed the social network structure for ecoregion-scale planning.•Despite shared concern about wildfire, organizations comprised distinct networks.•Organizations with different goals and geographic foci comprised distinct networks.•Social network ties among organizations were stronger at the sub-ecoregion scale.•Network analysis can quantify social capacity for landscape planning. Management of ecological conditions and processes in multiownership landscapes requires cooperation by diverse stakeholder groups. The structure of organizational networks – the extent to which networks allow for interaction among organizations within and across ideological and geographic boundaries – can indicate potential opportunities for cooperation on landscape-scale problems. In the arid landscapes of the western United States, where increasingly large wildfires burn irrespective of property boundaries and land designations, organizations involved in the restoration of forests and the protection of property from wildfire could benefit from working together to share information and coordinate strategies. We investigated patterns of interaction among organizations concerned with increasingly uncharacteristic wildfire risk in the Eastern Cascades Ecoregion of Oregon for evidence of structural conditions that create opportunity for cooperation. Through social network analysis of interview data, we found that despite sharing concern about wildfire risk in an area with a common set of ecological conditions, organizations with forest restoration and fire protection goals comprised distinct networks, as did organizations that focused on different geographic areas of the ecoregion. When interpreted through the lens of social capital and organizational theory these findings raise questions about the extent to which the structure of the organizational network reflects capacity to address wildfire risk in fire-prone forests on the ecoregion-scale. This study provides insights on the utility of a structural approach for investigating social capacity for landscape-scale planning.