- March 3 – Construction workers rupture a gas line outside the food court entrance of the Springfield Mall in Springfield, causing the mall's evacuation.
- March 6 – 53-year-old Richard Schaefer is shot to death by his estranged wife, 46-year-old Patricia S. Schaefer, on the front porch of her home at 3908 Prosperity Avenue in Fairfax.
- March 7 – Carl R. Peed is appointed Sheriff of Fairfax County by a panel of Circuit Court judges led by Lewis H. Griffith, replacing the departed M. Wayne Huggins.
- March 18 – 34-year-old Henry L. Boone is shot several times and mortally wounded at 3804 El Camino Place in Alexandria. Boone is taken to Inova Fairfax Hospital, where he dies on the morning of March 22.
- March 20 – 40-year-old John P. Langford fatally shoots his 36-year-old estranged wife Betty with a .44 magnum handgun in his home at 7047 Canterbury Lane in Alexandria.
- March 26 – By a 6 to 3 vote, the Fairfax County Board of Supervisors approves a scheme to sell $330 million in revenue bonds to finance construction of the Fairfax County Parkway. By choosing to issue revenue bonds, the BoS avoids having to allow county voters to approve a referendum, which would be required for general obligation bonds, but incurs an additional $3.5 million in interest charges.
- "Gas Line Break Clears Springfield Mall." The Washington Post (1974-Current file): 1. Mar 04 1990. ProQuest. Web. 18 Aug. 2014.
- Davis, Patricia. "Annandale Wife Charged in Fatal Shooting." The Washington Post (1974-Current file): C1. ProQuest Historical Newspapers: The Washington Post (1877-1995). Jun 08 1990. Web. 3 Mar. 2012.
- "Peed Interim Fairfax Sheriff." The Washington Post (pre-1997 Fulltext): d.07. National Newspapers Core. Mar 08 1990. Web. 12 Mar. 2012.
- "CRIME WATCH." The Washington Post (1974-Current file): 1. Mar 29 1990.ProQuest. Web. 27 July 2016.
- Brown, DeNeen L. "Estranged Wife is Slain in Fairfax County Home." The Washington Post (1974-Current file): 1. Mar 22 1990.ProQuest. Web. 15 Aug. 2016.
- Brown, DeNeen L. "Slain Woman's Kin Angry that Husband Wasn't Charged." The Washington Post (1974-Current file): 2. Sep 20 1991. ProQuest. Web. 15 Aug. 2016.
- Heath, Thomas. "Fairfax Approves $330 Million in Parkway Bonds." The Washington Post (1974-Current file): 2. Mar 27 1990. ProQuest. Web. 6 Apr. 2014.
|Fairfax County by Year: 1990|
|February 1990||·||March||·||April 1990|