The Great Northern Conference had been created in 1945 with Oregon Clay, Maumee, Perrysburg, Rossford, Sylvania and Toledo Whitmer as its charter members. Anthony Wayne would join them in 1953. League expansion was brought up in 1956 as Bowling Green, Fostoria, Swanton, Oak Harbor, Genoa, Lake, Port Clinton, Toledo Rogers and Holland were considered for membership. The GNC eventually grew and split into two divisions based on size— Orange: (Bowling Green, Clay, Fostoria, Toledo Rogers, Sylvania, and Toledo Whitmer) and Blue: (Anthony Wayne, Genoa, Maumee, Perrysburg, Port Clinton and Rossford). The names were changed in 1957, with the Orange Division becoming the Great Lakes League and the Blue Division becoming the Northern Lakes League.
Great Northern Conference Divisions (created in 1956)
Orange / Great Lakes League
Blue / Northern Lakes League
The NLL begins for the 1956-57 school year with Anthony Wayne, Genoa, Maumee, Perrysburg, Port Clinton, and Rossford as its charter members.
Eastwood joins in 1959 after being accepted in 1958.
For the 1996-97 school year, Lake leaves to join the SLL, and is replaced by Northview, who leaves the former Great Lakes League. The football team remained in the GLL for the 1996 season before fully joining at season's end.
Around 1999, Rossford first considered leaving the NLL for a league with members closer in their size. The 9-member SLL offered an opening, but Rossford initially declined.
In 2008, Rossford sent a letter of interest to be considered as the replacement for Lakota in the SLL, who left for the MAL in 2009. The SLL could not get a 6-out-of-7 vote to accept Rossford, ensuring they would remain a member of the NLL for at least a few more years. The NLL considered adding Clay and Napoleon to make a ten-school league, but a majority vote was not reached to expand.
In May 2009, Rossford's board of education voted unanimously to leave the Northern Lakes League and form the new Northern Buckeye Conference with Eastwood, Genoa, Lake, Otsego, and Woodmore, all schools that were withdrawing from the Suburban Lakes League. Later additions to the NBC included Elmwood and Fostoria. The new league began competition in the fall of 2011.
In June 2009, Napoleon High School accepted the invitation to join the Northern Lakes League in 2011 as the replacement for Rossford.
In August 2009, Maumee's school board voted 3-2 to remain members of the Northern Lakes League and to not accept the NBC's invitation to join their new league.
In January 2021, the NLL announced a plan to expand the league to 16 members, with two divisions of eight schools each based on enrollment. Any schools interested in membership were invited to apply, and it was hinted that expansion would most likely affect the Three Rivers Athletic Conference (TRAC) more than any other leagues.
On March 22, 2021, Maumee's school board voted unanimously to leave the NLL and join the Northern Buckeye Conference no later than the 2023-24 school year as a replacement for Elmwood High School.
On April 9, 2021, the seven remaining NLL schools sent invitations to four schools that are currently members of the TRAC: Findlay, Fremont Ross, Oregon Clay, and Whitmer. Fremont Ross voted to accept the invitation on April 12, followed by Findlay on April 19, Clay on April 20, and Whitmer on April 21.
On November 11, 2022, the NLL announced their division names and alignments for the 2023-24 through 2026-27 school years. The Buckeye Division will be for the larger schools and the Cardinal Division will be for the smaller schools, with a slightly different alignment for football. School enrollment will be considered every two years for reorganizing and balancing the divisions.
Buckeye Division (2023-24 & 2024-25) (based on OHSAA 22-23 & 23-24 final total enrollments)
Cardinal Division (2023-24 & 2024-25) (based on OHSAA 22-23 & 23-24 final total enrollments)
Buckeye Division Football (2023 & 2024) (based on OHSAA 19-20, 20-21, & 21-22 final total enrollments)
Cardinal Division Football (2023 & 2024) (based on OHSAA 19-20, 20-21, & 21-22 final total enrollments)