The Northwest Conference has been around since 1947 and has had numerous members come and go but still has 4 of its founding members in Allen East, Columbus Grove, Delphos Jefferson and Spencerville. The other current active members are Ada who joined in 1964, Bluffton who joined in 1953, Crestview who joined in 1970, Leipsic who joined in 2021, and Lincolnview who joined in 1965.

Paulding left the conference after the 2020-21 school year after joining 1967.
Lima Central Catholic left the conference after the 2012-2013 school year after joining in 2006.
Perry left the conference after the 2003-2004 school year after joining in 1960.
Upper Scioto Valley left the conference after the 2000-2001 school year after joining in 1966.
Elida left the conference after the 1970-1971 school year after being a founding member in 1947.
Gomer left the conference after the 1968-1969 school year after joining in 1956.
North Baltimore was a football only member and left the conference after the 1968 football season after joining in 1967.
Ottawa-Glandorf was a football only member and left the conference after the 1966 football season after joining in 1964.
Pandora-Gilboa was a football only member and left the conference after the 1965 football season after joining in 1947.
Bath left the conference after the 1964-1965 school year after joining in 1962.
Beaverdam left the conference after the 1963-1964 school year after joining in 1956.
Leipsic was a football only member and left the conference after the 1963 football season after joining in 1962.
Forest was a football only member and left the conference after the 1961 football season after joining in 1947.
Shawnee was a football only member and left the conference after the 1952 football season after joining in 1947.