The theory and practice of participatory mapping (PM) has expanded significantly over the last two decades with proliferation of a wide range of methods and applications. The potential for synthesis and integration across four broad domains of PM (indigenous/rural/community, urban/regional, environmental/natural resource, and mapping technology) was examined at the Participatory Mapping/GIS 2017 conference held at California Polytechnic State University (San Luis Obispo, USA) Jul 31-Aug 3, 2017. At the conference, PM leaders in each of the four domains participated in working groups to: (1) identify the key issues, including “barriers” and “knowledge gaps” that limit effective PM outcomes, and (2) identify the most important research priorities. This paper summarizes the findings of the working groups for the purpose of identifying common and unique challenges across the four PM domains and to discuss the desirability of stronger integration of PM knowledge and practice. In the indigenous/rural/community domain, achieving clarity in PM purpose and building trust in the process were identified as the most critical issues; in the environmental/natural resources domain, wider use and adoption of PM to inform policy and management decisions through stakeholder engagement was considered most important; and in the urban/regional domain, developing urban indicators and adapting PM to complex and heterogeneous urban environments were identified as important needs. The key issue in the domain of PM technology was understanding how technology influences PM usability and user behavior for the development and implementation of appropriate PM technology. The most significant cross-cutting theme to emerge across all PM domains was the need to evaluate PM outcomes to provide evidence of success.