The conference was formed in the spring of 1925 with seven original members: Antioch, Arlington, Barrington, Libertyville, Palatine, Warren, and Wauconda.
[1] The conference had a stable lineup for 16 years until 1973, when Lake Forest left for the North Suburban and the NWSC added three new members: Cary-Grove, Stevenson, and Woodstock.
With two more additions in 1976, Dundee and Jacobs, the NWSC had 12 members, and the conference was split into North and South divisions for football.
The division format lasted only two seasons, however, as membership reduced down to 8 after Cary-Grove, Dundee, Jacobs, and Woodstock all left in 1978 to create the Fox Valley Conference.
[1] After Grayslake and Marian Central left in 1997 to join the Fox Valley and Suburban Catholic Conferences, respectively, the NWSC officially folded.