Most Arlington County Public School students will start back to school Tuesday, September 6th, 2011. Barcroft Elementary which is a year round school has already begun classes. Elementary School students will get a five day weekend October 5th-10th with parent teacher conferences on the 5th and 6th and the Columbus Day Holiday on the 10th (middle schoolers have Friday the 6th and the 10th off while high schoolers just have the 10th). Winter Break runs from December 23rd through January 2nd with students returning to class on January 3rd. Spring Break begins the weekend of March 31st and runs through Monday, April 9th unless Monday is needed as a make-up day.
For the complete calendar including early release days, teacher work days and other holidays go to this link.