Va. Code § 15.2-3227
Except by mutual agreement of the governing bodies affected, no city or town, having instituted proceedings to annex territory of a county, shall again seek to annex territory of such county within the 10 years next succeeding the effective date of annexation in any proceeding under this article or previous acts. In the event annexation is denied, such prohibition shall begin with the date of the final order of the court denying annexation or, in the case of an appeal to the Supreme Court or the Court of Appeals, with the date of the final order of the Supreme Court or the Court of Appeals. However, a city or town moving to dismiss the proceedings before a hearing on its merits may file a new petition five years after the filing of the petition in the prior suit. No county shall, except with the consent of its governing body, be made defendant in any annexation proceeding brought by any city within such 10-year period.
Notwithstanding the foregoing provisions, a city shall have the right to file and maintain an annexation proceeding against any county against which it has not filed such a proceeding during the preceding 13 years.
The provisions of this section shall not apply to any petition for annexation brought by a city or town, within such 10-year period, if the previous petition was dismissed due to a procedural defect, lack of jurisdiction, or any defense other than the merits of the case. The provisions of this section shall not apply to a city or town that institutes an annexation proceeding by filing notice with the Commission on Local Government but which subsequently fails to petition the court to grant such annexation. In that event, however, the city or town shall not again institute proceedings for annexation against the county for at least two years after the date the Commission renders its final report on the initial proceeding.
This section shall also apply to any city that was a town at the time of the filing of such petition.
Va. Code § 15.2-3227