Alva, Wyoming  Alva is an unincorporated community in north central Crook County, Wyoming, United States. It lies along WYO 24 34.9 miles north of the town of Sundance, the county seat of Crook County and 9.7 miles away from Hulett, Wyoming. Its elevation is 3,993 feet (1,217 m), and it is located at (44.694707, -104.441342). Although Alva is unincorporated, it has a post office, with the ZIP code of 82711. Population is 50. Public education in the community of Alva is provided by Crook County School District #1. According to the Köppen Climate Classification system, Alva has a semi-arid climate, abbreviated "BSk" on climate maps.