Stone Bridge opened in 2000, with its student body coming from Broad Run High School and Loudoun County High School. It opened the same year as two other Northern Virginia high schools, Forest Park Senior High School opened in Prince William County, and Westfield High School opened in Fairfax County; all three schools regularly played against each other in many sports in their inaugural year. The school's capacity is at around 1,600 students.During the first year, there were nearly 1,200 students from 9th through 11th grade; seniors stayed at Broad Run or Loudoun County. There were also nearly 500 8th graders housed at Stone Bridge during the 2000-2001 school year because of overcrowding at Harper Park Middle School, the feeder middle school at that time.In 2002, most of Stone Bridge's Leesburg student body (except for Lansdowne residents and upcoming seniors if they chose so and could provide their own transportation) were moved to Heritage High School, but some additional students from Broad Run were moved to Stone Bridge, dropping enrollment to roughly 1,400 students in the 2002-2003 school year. However, by the 2004-2005 school year, the student body went up to nearly 1,900 students, the biggest enrollment at the time for a Loudoun County high school. In 2005, Briar Woods High School's opening helped alleviate crowding, but its enrollment remained above 1,600 students.In 2010, the rest of Stone Bridge's Leesburg student body was transferred to Tuscarora High School to relieve overcrowding. Stone Bridge will be shifting students who live inside Belmont Country Club to Riverside High School in 2015. This will drop the enrollment by roughly 500 students.