The Northwest Border Conference is a former high school athletic conference comprising small public high schools along the St. Croix River in northwestern Wisconsin. The conference existed from 1940 to 1956, and all member schools were affiliated with the Wisconsin Interscholastic Athletic Association.
The Northwest Border Conference was founded in 1940 from a split of the ten-member Upper St. Croix Valley Conference. The five smallest schools in that conference (Balsam Lake, Centuria, Luck, Milltown and Webster), joined with Siren (previously an independent) to form the original six-member roster. Members were located in Burnett and Polk Counties, and all but one (Balsam Lake) were located along Wisconsin Highway 35. After only two seasons in the conference, Milltown returned to the Upper St. Croix Valley Conference in 1942, leaving the conference with five members. That same fall, the Northwest Border Conference began sponsorship of eight-player football with all members participating. Luck followed Milltown back to the Upper St. Croix Valley Conference in 1947 and were replaced by Somerset that same year, though they didn't join for football until the next year. The Northwest Border Conference competed as a five-member loop until Webster rejoined the Upper St. Croix Valley in 1953. Solon Springs, who competed as an independent for other sports, was a football-only member of the conference for the 1953 and 1954 seasons. After Somerset left for membership in the Dunn-St. Croix Conference in 1955, Solon Springs joined for the conference as full members for its final season. After the Northwest Border Conference's demise, three of its former members joined the Lakeland Conference: Balsam Lake and Centuria in 1956 and Siren in 1959. Solon Springs competed as an independent before joining the Indianhead Conference in 1968.