- July 19 – 45-year-old Alexander C. Bridewell, III shoots his 47-year-old wife Barbara Jane to death, then commits suicide in the couple's home at 5555 Renoir Port Lane in Burke.
- July 23 – 18-year-old Kendra L. Geter pleads guilty to involuntary manslaughter for fatally stabbing 22-year-old Rita Morris in the back during a fight between Morris and Geter's mother Martha at the Statesman Motel in Alexandria on April 26.
- July 23 – By a 7-0 vote, the Fairfax County Board of Supervisors approves an ordinance allowing developers to build at a 20% higher density than otherwise zoned in exchange for setting aside 12½% of the units constructed for purchase or rental by people with low incomes.
- "Murder-Suicide Suspected in Fairfax Couple's Deaths." The Washington Post (pre-1997 Fulltext): 0. Jul 20 1990. ProQuest. Web. 16 Aug. 2014.
- Wolfe, Frank. "Plea deal struck in slaying at shelter." The Washington Times, 24 Jul. 1990, 2, BMETROPOLITAN, p. B3. NewsBank. Accessed 1 Jan. 2018.
- "Fairfax County(2)." The Washington Post (1974-Current file): 1. Jul 26 1990. ProQuest. Web. 26 Aug. 2014.
|Fairfax County by Year: 1990|
|June 1990||·||July||·||August 1990|