I
The seeding
Before a down is played, every county in the fifty states is dealt to the FBS program with the nearest stadium, measured as the crow flies from the county's geographic center. Nobody starts landless in the FBS; nobody outside it starts with anything.
II
The conquest
When a game goes final, the winner takes everything the loser holds at that moment: home soil and every prior conquest alike. Games are replayed in kickoff order, so an empire can rise and fall inside a single Saturday.
III
The raid
A team with no land has nothing to lose, but it can beat any landholder and take the lot. That is how FCS, Division II and Division III programs raid their way onto the map, and land taken downward can stay there all season.
On the carousel map, land carries over from season to season since 2014 and stays with the program when a coach leaves; a program that opens a season landless gets its home counties back if it hired a new head coach. Ties, unfinished games and games without a score are ignored. Territories (Puerto Rico, Guam, the Virgin Islands) are off the map. Neutral-site games overseas do not yet award foreign soil. A week appears in the timeline once its first game goes final. The current map is refreshed automatically every morning during the season. The 2018 campaign is complete. Stadium coordinates, colors and logos are today's; conference and division come from each season's own results. The full rules and methodology have the details.