State Route 123 is a state highway located in the state of Virginia. It runs primarily through Fairfax County and connects several important areas, including Lake Accotink Park and Mason Neck State Park. The route serves as a vital link for local traffic and provides access to various residential and commercial zones. The highway is approximately 10 miles long and is known for its scenic views, particularly as it passes through wooded areas and near bodies of water. State Route 123 is also significant for commuters, as it connects to major roads and highways, facilitating travel within the region.