Because it isn't always easier to google it; here is the 2018-2019 Loudoun County Public School Calendar. Also, how it is almost 2019?!
August 23:First Day of School
September 3: Holiday (Labor Day)
October 8: Holiday (Columbus Day)
October 22: Student Holiday (County-wide Staff Development)
November 2: End of the Grading Period
November 5-6: Student Holidays (Planning/Records/Conference Days)
November 21-23: Holiday (Thanksgiving)
December 21-January 1: Winter Break (Classes Resume January 2)
January 17: End of Grading Period
January 18: Moveable Student Holiday** (Planning/Records/Conference Day)
January 21: Holiday (Martin Luther King Jr. Day)
February 18: Holiday (Presidents’ Day)
March 28: End of Grading Period
March 29: Student Holiday (Planning/Records/Conference Day)
April 1: Student Holiday (County-wide Staff Development)
April 15-19: Holiday (Spring Break)
May 27: Holiday (Memorial Day)
June 7: Last Day of School/End of Grading Period