As Prince William County grew, Battlefield High School of Haymarket opened and joined the district in 2004.
A preliminary plan had two additional Loudoun County schools joining the district with Heritage High School of Leesburg coming from Group AA, and Stone Bridge High School of Ashburn coming from the Liberty District and AAA Northern Region.
In addition, Osbourn Park is also expected to move back to the Cardinal District.
However the preliminary plan was not passed and Stone Bridge was granted the right to stay in the Northern Region, Liberty District.
Starting in the 2009/2010 school year the Cedar Run only had five members; Heritage, Loudoun Valley, Battlefield, Stonewall Jackson, and Osbourn.