By default, units are garrisoned by pressing G and then clicking on a building. There is also the option to garrison units by just right-clicking on a building, it can be enabled by checking One Click Garrison in the Options → Mouse.
Garrisoned friendly buildings have a small waving flag above them. Note that the flag is not an accurate representation of the exact amount of garrisoned units within a building.
Garrisonable structures Edit
- City Centers can be garrisoned by all types of land units except Auto Plant vehicles. Small cities have a capacity of 10 units, large cities 15 units and major cities 20 units. Cities with less than 10% hit points cannot be garrisoned until repaired, and cities being assimilated cannot be garrisoned.
- Towers can be garrisoned by all types of land units except Auto Plant vehicles and Artillery Weapons. Towers have a base capacity of 5 units, which can be upgraded to a maximum of 11 by researching Fortification technologies at a Fort.
- Forts can be garrisoned by all types of land units. Forts have an initial capacity of 10 units, upgradeable to 25 by researching Fortification technologies at the Fort.
- Units created at an Airbase or Missile Silo automatically garrison inside the structure and receive orders from it (except for helicopters). Fighters and Bombers return to their airbase after completing a mission. The Airbase has a capacity of 10 units, the Missile Silo holds 1 unit.
- Land and sea units can also always garrison inside the type of building that created them. Barracks and Stables/Auto Plants have a capacity of 10 units, Siege Factories/Factories and Docks 20 units.
Note that large units like siege/artillery units or ships take up extra garrison space. Also note that if cavalry units are upgraded to vehicles, they will stay garrisoned (despite the fact that vehicles cannot be garrisoned inside a Fort). However, once evacuated from the Fort, they cannot garrison it again.
Garrisoned troops are automatically evacuated from a structure, before it is destroyed, taking no extra damage from this. An exception to this are Airbases and Missile Silos - garrisoned units are destroyed along with these structures. Air units currently on a mission will attempt to find a new Airbase to land if their own base is destroyed.
Garrison Power EditCities, Towers and Forts all have the ability to attack enemy units within medium range. The number of projectiles fired from a building is listed in the structure's stat box as Garrison Power (GP, see right) and, as the name implies, it somewhat depends on units garrisoned inside. Towers have an innate Garrison Power of 1 while Forts have an innate Garrison Power of 2, which allows them to attack without any units garrisoned inside; however, garrisoned units will vastly improve their attacks. Cities on the other hand cannot attack without units garrisoned inside. Cities do count as having half of the attack strength already garrisoned, making it much easier to reach the first Garrison Power; for example, only 2 Citizens are needed for a Small City to have a Garrison Power of 1, while 6 Citizens are needed for a Garrison Power of 2.
With enough units garrisoned inside, a Small City gains up to two attacks, a Large City gains up to three attacks, a Major City gains up to four attacks, a Tower gains up to two additional attacks, and a Fort gains up to four additional attacks. Note that if the Hit Points of a City are reduced to zero, all garrisoned units are automatically ejected. Furthermore, a city with zero HP cannot be used for Garrison.
However, only Infantry units, Citizens and Scholars will contribute to a building's Garrison Power and the number of units required to increase GP by 1 depends on the garrisoned units' individual strength, with melee units only counting half their strength. As units get stronger through the ages, it becomes easier to fulfill the requirements to increase a building's Garrison Power. Garrisoned Citizens will contribute strength as if they were Militia/Minuteman/Partisan if those upgrades have been researched, without having to use the "To Arms!" command.
Garrisoned units automatically heal at a slow rate. The default healing rate is 1 hit point per 1.33 seconds. This rate can be increased by researching various technologies at the Granary: With Herbal Lore the healing rate increases to 1 hit point per second, with Medicine to 1 hit point per 0.66 sec and with Pharmaceuticals to 1 hit point per 0.33 sec. Aircraft heal at a slightly slower rate, while ships heal at an increased rate when garrisoned.