<div>What is social infrastructure? How is it defined, if at all? This paper importantly brings together cross-disciplinary discussions that are often about social infrastructure. Examining social infrastructure in rural and northern Ontario to draw connections between reports of hidden homelessness, discussions about or in reference to social infrastructure, and the realities faced by rural and northern Ontario municipalities and communities. Using a review and analysis of these different streams of research, social infrastructure spaces are mapped according to different definitions or understandings in the disciplines. This mapping exercise is applied to Sault Ste. Marie to illustrate the complexities of addressing social issues as they unfold in small northern Ontario communities. The research suggests that a broader understanding of what social infrastructure is can help us to see spaces that are often overlooked and</div><div>underappreciated by planners, but perhaps valued by individuals experiencing hidden homelessness for the sociality and comforts that they can provide. This suggests that in addressing homelessness, poverty, and economic revival, planners in rural, small, and northern communities ought to think critically about the ways in which planning policies, programs and strategies might overlook spaces use by those most marginalized.</div><div><br></div><div>Key words: social infrastructure, hidden homelessness, rural and northern Ontario, Sault Ste.</div>