A distribution is simply a subset of territories that determine where players will start. Any territory that is in the distribution will be available for players to start on. Territories not in the distribution will start as a neutral with the game's non-distribution neutrals value.
For example, the "Warlords" pattern distribution selects one territory from each bonus and leaves the rest empty. This causes the map to start mostly neutral and players will expand slowly. Another pattern is the "Cities" distribution where you select all territories on the map except for one in each bonus. Game creators can then set the neutrals very high and create a barrier to obtaining each bonus.
All maps get three built-in normal distributions: full distribution (all territories included), random cities and random warlords. These can't be turned off by map creators, and will always be available. Map creators can also supply additional distribution options for their map.
 Even Distribution
When using a normal distribution, Warzone ensures that each player will always receive the same number of territories as all other players. If the selected map distribution does not divide evenly into the number of players then the remaining territories will be made neutral.
 Limit Distribution
Game creators can optionally set a territory limit on the number of territories that each player receives. When using a limit, the map's distribution is still obeyed. If a limit is set and reached, the territories in the map's distribution that did not get distributed to a player will be made neutral.