Ohio East/Southeast Regions defunct athletic conferences
This is a list of former high school athletic conferences in the East and Southeast Regions 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. Adams County League. The ACL was one of the local small-school county leagues in Southwest Ohio. Consolidation reduced the number of teams to five by 1964, and in 1970 these five joined with the Brown and Highland county leagues to form the Southern Hills Athletic League. Belmont County League. "A" Division "B" Division Buckeye Border Conference (East). This was a conference located in far eastern Ohio, with many schools who maintained  membership in the Ohio Valley Athletic Conference. This conference should not be confused with the Northwest Ohio league of the same name. Cardinal Conference. Note: The Ohio Cardinal Conference was created in 2003 to preserve the legacy of the former Cardinal Conference. Carroll County League. One of the smallest county conferences, the CCL lasted until two of its members consolidated in 1962, while the other two schools had been playing in other leagues concurrently with the CCL. East Central Ohio League (old). This early incarnation of the ECOL functioned mostly as a football league and secondary league for schools who  also participated in local county leagues. The conference would never find its legs, as it spent its last eight years with only four members. Fairfield County League. This league had many members concurrently with the Mid-State League, and ended when Pickerington, the last remaining non-MSL member, joined the MSL in 1966. Fayette County League. This small league contained all of the county schools outside of Washington Court House. New Holland, which sits on the border between Fayette and Pickaway Counties, played in the Pickaway County League until moving to the FCL in 1958 for its final two seasons . Highland County League. The HCL was one of the local small-school county leagues in Southwest Ohio. The league had eight schools for most of its history, but consolidation chipped away at its membership total. League membership had been reduced to three by 1969,and these teams struggled on for a year until the creation of the Southern Hills Athletic League, which saw the three combine with the Adams and Brown county leagues, who had five teams apiece at that point. Hocking County League. This was one of the few county leagues that folded while still having enough members for competition , as the four schools left for different leagues. Mid-Ohio Valley Conference. This short-lived bridge conference should not be confused with what would eventually become the Pioneer Valley League. While both leagues used the Mid-Ohio Valley name at the same time, this operated more in the Southeast Region, while the eventual PVL more closely aligned with the East Region. All schools in this conference were eventually members of the TVC by either joining after leaving the Mid-Ohio Valley Conference or by consolidating into a school that eventually joined. Glouster, McArthur, and Rutland all joined by consolidating into  Trimble, Vinton County, and Meigs. All members are still currently in the TVC except Miller and Wahama, who both left following the 2019-2020 school year. Perry County League. Originally a 12-school conference encompassing all Perry County schools, the league settled into a stable, nine school league as the independent schools moved to the Muskingum Valley League. This was abruptly changed in 1960, as consolidation dropped the number from nine to two new consolidated schools. Pickaway County League. Another of the old County leagues for smaller schools, the league suffered from the rapid consolidation of schools in Pickaway County  in the early 1960s. The league went from eleven schools in 1959 to four in 1963, with those four consolidating that next year. Pioneer Valley Conference. The PVC originally formed in 1964 as the Frontier Valley Conference, then became the Mid-Ohio Valley Conference in 1966 to avoid confusion with the newly consolidated Frontier Local School District. The conference settled on its current moniker in 1976 before dissolving in 2019. River Valley Conference. This was a short-lived conference in the 1990s to help some Ohio Valley Athletic Conference teams with scheduling. Ross County League. Another County League that folded  despite having ample competition, the league ended when the remaining members who weren't already affiliated with the Scioto Valley League members joined that conference in 1975. Scenic Hills Conference. A short-lived "bridge" conference for newly consolidated and larger schools until the Inter-Valley Conference was formed. Scioto County League. The conference ended in 1979 as the non-Southern Ohio Conference affiliated members, who maintained affiliation with the Tri-County League, moved to the SOC while keeping TCL ties intact. Southeastern Ohio Athletic League. The SEOAL was Ohio's oldest non-city athletic league, founded in 1925. The 2016 -2017 school year was the final year the SEOAL existed as a conference ending a long tenure of historic rivalries. Controversy surrounded Athens and Marietta's exits as no real reason was given but wide speculation was that it was due to them being unable to compete with the other schools on a regular basis. No all-sports trophy was awarded due to only having three members in the final year. From 2006-10, the SEOAL played in North and South divisions: Southern Valley Athletic Conference. Originally the Gallia County League, the conference changed its name to the SVAC in  1958 with an eye on expanding the league to protect against future consolidations. The conference fell apart in 1992, as it was reduced to three schools, and limped along until those three found conference homes that next year. Tri-County League (Southeast). This league started in 1964 with the dissolution of the Pike County League. The two schools not already in other conferences joined with schools from neighboring Adams and Scioto counties that wanted a secondary conference to fill their schedules. These schools largely ended up in the Southern Hills Athletic Conference or the Southern Ohio Conference by the time  the league wound up in 1985. Tuscarawas Valley Athletic Conference. Formed as some of the Tuscarawas County schools proved to be too large to face sufficient competition in the county league, these schools banded together with other larger schools in the area. The league ended in 1968, as the largest schools joined the dwindling Stark County AA League schools to form the Senate League, and most of the other schools helped found the Inter-Valley Conference.