- July 4 – Lawrence G. Emmer is stabbed to death in his Great Falls home at 1223 Colvin Meadows Lane by his son, Casey.
- July 9 – Following a two year long renovation and expansion project, the Dolley Madison Library in McLean reopens.
- July 19 – Gary P. Hanson is shot to death by his son, Richard, in the elder Hanson's Springfield home.
- July 21 – Refusing police commands to drop the shotgun he is carrying, 34-year-old Ricardo Leon is shot to death by Fairfax County Police officers in front of his townhouse at 6165 Kendra Way in Centreville.
- July 22 – 62-year-old Vienna woman Barbara Newman stops by Dr. Mark A. Lawrence's home and office at 8612 Tebbs Lane in McLean and shoots the 71-year-old psychiatrist to death before committing suicide.
- July 28 – Following allegations of visa fraud, agents from Immigration and Customs Enforcement and other federal agencies raid the offices of the University of Northern Virginia in Annandale.
- Wu, June Q. "Man, 25, Charged in Father's Slaying." The Washington Post: B.8. National Newspapers Core. Jul 06 2011. Web. 5 Oct. 2011.
- Fairfax County Public Library. Dolley Madison Library to Open July 9. Fairfax County Public Library, 22 June 2011. Web. 25 June 2011.
- Zapotosky, Matt. "Springfield Man Charged in Father's Fatal Shooting." The Washington Post: B.3. National Newspapers Core. Jul 22 2011. Web. 1 Oct. 2011.
- Stachyra Lopez, Mary. "Police Shoot, Kill Armed Man on Kendra Way." Centreville Patch. Patch.com, 21 July 2011. Web. 14 July 2014.
- Noble, Andrea. "Man Fatally Shot by Fairfax Police Was DoD Security Officer." Washington Times. The Washington Times, 22 July 2011. Web. 14 July 2014.
- Hendry, Erica R. "Vienna Woman Identified In Suspected Murder-Suicide" Vienna, VA Patch. Patch.com, 23 July 2011. Web. 21 Oct. 2011.
- Vise, Daniel De. "Feds Raid Northern Virginia University." Washington Post. The Washington Post, 01 Aug. 2011. Web. 08 Oct. 2012.
|Fairfax County by Year: 2011|
|June 2011||·||July||·||August 2011|