Any county with a population of more than 90,000 may adopt the urban county executive form of government in accordance with the provisions of Chapter 3 (§ 15.2-300 et seq.) of this title.
Va. Code Ann. § 15.2-801, under Chapter 8. Urban County Executive Form of Government..
Va. Code Ann. § 15.2-801
Any county with a population of more than 90,000 may adopt the urban county executive form of government in accordance with the provisions of Chapter 3 (§ 15.2-300 et seq.) of this title.