This is a list of former high school athletic conferences in the Northwest Region of Ohio, as designated by the OHSAA. If a conference had members that span multiple regions, the conference is placed in the article of the region most of its former members hail from. Because the names of localities and their corresponding high schools do not always match and because there is often a possibility of ambiguity with respect to either the name of a locality or the name of a high school, the following table gives both in every case, with the locality name first, in plain type, and the high school name second in boldface type. The school's team nickname is given last.