This article investigates whether and how the contexts of the Rust Belt decline extend collaborative planning theory. We evaluate two collaborative planning projects in Northeast Ohio: (1) the Cuyahoga Greenways (CG), a regional trails project and (2) the Mahoning River Corridor Initiative (MRCI), a postindustrial river restoration project. Based on participant interviews and document analysis, we find that the projects are distinct in their contextual conditions and collaborative processes, with CG better aligning with common expectations found in the literature. MRCI deviates from normative theory pertaining to collaborative planning; we discuss how this might relate to processes of institutional change. Our results suggest that the collaborative planning literature is insufficiently tailored to assess collaborative projects in the context of decline—particularly where there is controversy around the project and where collaborative institutions and networks are weak.