The Prince William County / Manassas City Championship was established in the Spring of 2007. The Championship consists of all 10 schools in Prince William County and the 2 schools in Manassas City. Ten of the twelve schools are from the AAA classification and 2 are from AA.

The Cardinal District schools compete in the AAA Northwest Region with the schools from the AAA Cedar Run District, the AAA Commonwealth District, and the AAA Western Valley District.

All Cardinal District schools are currently located in eastern Prince William County of Northern Virginia which draws students who live in Woodbridge, Dale City, and Dumfries. Currently, Prince William County schools are split between the Cardinal and the Cedar Run Districts due to the high amount of growth in the county, but all Prince William schools were in the Cardinal District until 2001. The smallest school in the Cardinal is Potomac with an enrollment at around 1,400 and the largest member is Woodbridge with an enrollment at around 2,600. Potomac has a AA enrollment, but chooses to play up in AAA to maintain rivalries rather than play in the AA Northwestern District or AA Battlefield District whose member schools are farther away. Potomac's enrollment is also projected to increase back into the AAA level in the near future.

The Northwest Region is one of the four AAA regions in the Virginia High School League. It is made up of four districts: the Cardinal District, the Cedar Run District, the Commonwealth District, and the Western Valley District. Group AAA is the largest enrollment class for VHSL schools.

The Northwest Region's member schools covers the largest geographic area of the four AAA regions, stretching from the outer suburbs of Northern Virginia primarily in Prince William County and Stafford County, to Southwest Virginia.