The Empty Grave Haunted House in Longmont, CO serving the greater Denver Metro area, The Empty Grave is located near Wibby Brewing in Downtown Longmont. The Empty Grave Haunted House is an imersive, interactive walk through haunted attraction servicing Adams County, Boulder County, Weld County. A short drive from Denver proper, The Empty Grave Haunted House puts you face to face with your fears. Your adventure will feature encounters with the menacing, workers of a haunted factory, as you attempt to survive your first night on the grave yard shift. Do you have what it takes to survive?