The Northern Illinois Big 12 Conference was a high-school athletic conference with ten high schools in northern Illinois. The conference began competing during the 2010–2011 academic year and dissolved following the 2018–2019 academic year. In many respects, including membership and organization, the NI-Big 12 was much like a reboot of the old North Central Illinois Conference (NCIC). Six of the schools were former members of the North Central Illinois Conference (1929-2011), and the conference was divided into two divisions, much as the NCIC was for decades. The former NCIC schools were Geneseo, LaSalle-Peru, Sterling, Ottawa, and Rochelle. Also, there were five schools that were members of the Western Sun Conference (2007-2010). The former Western Sun Schools are DeKalb, Kaneland, Sycamore, Yorkville, and Rochelle, which left the NCIC in 2007 to join the WSC, and was thus a member of both extinct conferences.