- October 5 – 20-year-old Carol N. Lutsky beats and mortally injures her girlfriend's son, 11-month-old Nehemiah Williams, in her home in Vienna. Nehemiah is taken to the Children’s National Medical Center in Washington, D.C., where he dies the next day.
- October 6 – 50-year-old Carmela Dela Rosa is convicted of first-degree murder in the November 29, 2010 slaying of her 2½-year-old granddaughter, Angelyn Ogdoc, whom she threw from a 44-foot high walkway at Tysons Corner Center.
- October 14 – The Colonel William L. Durrer Police Forensic Facility, named for the former Chief of Police, is dedicated at the McConnell Public Safety and Transportation Operations Center in Fairfax. The dedication is attended by Col. Durrer, his wife Ayleen, Chairman of the Fairfax County Board of Supervisors Sharon Bulova, and current Fairfax County Police Chief Colonel David M. Rohrer.
- "Vienna Police Call Death of Baby Suspicious." NBC4 Washington. NBCUniversal Media, 13 Oct. 2011. Web. 04 June 2014.
- "Woman to Serve 22 Years in Death of 11-Month-Old Boy." NBC4 Washington. NBCUniversal Media, 2 May 2014. Web. 04 June 2014.
- Jouvenal, Justin. "Dela Rosa Convicted of Murder in Throwing Granddaughter from Pedestrian Bridge." Weblog post. The Washington Post: The Crime Scene. The Washington Post, 6 Oct. 2011. Web. 7 Oct. 2011.
|Fairfax County by Year: 2011|
|September 2011||·||October||·||November 2011|