"Land area" means the total land area of the counties within a highway construction district reduced by the area of any military reservations and state or national parks or forests within its boundaries and such other similar areas and facilities of five square miles in area or more, as may be determined by the Board.
"Population" means the population according to the latest U.S. census or the latest population estimates made by the Weldon Cooper Center for Public Service of the University of Virginia, whichever is more recent.
Va. Code § 33.2-371