Spotsylvania County is a county in the U.S. state — officially, "Commonwealth" — of Virginia. As of the 2000 census, the population was 90,395. The Census Bureau predicts it to be at 119,529 in 2006, a 32.2% increase, making it the fourth fastest growing in the nation. The independent city of Fredericksburg is located in the northeast corner of the county but is politically separate.

This county is a part of the Washington Metropolitan Area because of its vast numbers of commuters that travel north on Interstate 95 or Virginia Railway Express (VRE) for work.

Spotsylvania County was established in 1721 from Essex, King and Queen, and King William counties. The county was named in Latin for Virginia Lieutenant Governor Alexander Spotswood.

Many battles were fought in this county during the Civil War, including the Chancellorsville, the Wilderness, Fredericksburg, and Spotsylvania Court House. Stonewall Jackson was shot and mortally wounded in Spotsylvania County during the Battle of Chancellorsville. A group of Confederate soldiers from North Carolina were in the woods when they heard the footsteps of General Jackson's party returning from a reconnaissance of Union lines. They mistook him for a Federal patrol and shot him in the arm. His arm was amputated, but he was unable to recover and died a few days later from pneumonia at nearby Guinea Station, where Confederate wounded were being gathered for evacuation to hospitals further south.