Montross is a town in Westmoreland County, Virginia, United States. The population was 553 at the 2020 census. It is the county seat of Westmoreland County. Located in the historic Northern Neck of Virginia, Montross is near the George Washington Birthplace National Monument and the Stratford Hall Plantation. The town's slogan is return to the vil…Montross is a town in Westmoreland County, Virginia, United States. The population was 553 at the 2020 census. It is the county seat of Westmoreland County. Located in the historic Northern Neck of Virginia, Montross is near the George Washington Birthplace National Monument and the Stratford Hall Plantation. The town's slogan is return to the village.