Northern Indiana Athletic Conference Former members Former members

| School | Location_ | Mascot | County | Joined | Previous_Conference | Left_ | Conference_joined |
|---|---|---|---|---|---|---|---|
| Plymouth | Plymouth | Pilgrims | 50 Marshall | 1927 | Independents | 1930 | Independents |
| South Bend Central * | South Bend | Bears | 71 St. Joseph | 1927 | Independents | 1970 | none (school closed) |
| Valparaiso | Valparaiso | Vikings | 64 Porter | 1927 1945 1953 | Independents Independents Independents | 1930 1948 1963 | Independents Independents Northwestern |
| Whiting | Whiting | Oilers | 45 Lake | 1927 | Independents | 1963 | Northwestern |
| East Chicago Roosevelt | East Chicago | Rough Riders | 45 Lake | 1929 | Little 7 | 1963 | Northwestern |
| Gary Wallace | Gary | Hornets | 45 Lake | 1935 | Little 7 | 1963 | Northwestern |
| Hammond Tech | Hammond | Tigers | 45 Lake | 1937 | Independents | 1963 | Northwestern |
| Gary Tolleston | Gary | Blue Raiders | 45 Lake | 1941 | Independents | 1963 | Northwestern |
| Hammond Clark | Hammond | Pioneers | 45 Lake | 1941 | Independents | 1963 | Northwestern |