Forts are to Dominions what cities are to Civilization: they are vitally important buildings that form the central nodes of economic and (most) magical activity. The construction of a fort is required for most national units and commanders to be recruited, and the forts themselves draw additional resources from neighboring provinces which make those units easier to recruit. Unlike labs and temples, forts take multiple turns to build. A few sites also generate forts upon discovery, and some rare events will create forts instantly. Some rituals also allow players to build forts in single turn during the magic phase.

Most national units and commanders require the construction of a fort (in addition to other necessary buildings) to recruit. Exceptions to this rule are indicated by hovering over the unit in the nation summary screen. Forts additionally facilitate the recruitment of these units in a number of ways:

• Forts provide a bonus to recruitment points for units as well as commanders.
• Forts unlock the full resource output of their province (provinces without forts only have half their true resources available), as well as drawing a percentage of the true resources of neighboring unforted provinces according to their admin value. If a province is surrounded by forts which have a combined admin > 100, it will have no resources left for itself and will no longer be able to recruit units or commanders.
• Land provinces do not draw resources from neighbouring underwater provinces or the other way around.

Forts also provide significant defensive and economic benefits:

• Enemy armies that conquer a province with a fort do not automatically capture it; they must first besiege it and destroy the walls before storming. Higher-tier forts will have more wall defenders when they are stormed.
  • While a fort is under siege, it will provide supply to the defending army equal to its Supply Storage divided by the number of turns since the siege began.
• A forted province's province defense will be nation-specific rather than being based on its original indie type. This can sometimes be a downgrade.
• Income may only be collected from a province if a path can be traced between it and a friendly fort.
• Forts increase the income of the provinces they are built in by a percentage equal to half of their administration value.
• Forts provide bonus supply to their province and nearby friendly provinces, depending on how far away they are. Bonus supply is equal to (admin × 4)/(distance + 1).¹⁾

Forts may be built by any commander in a province via the 'Build' command. Once the up-front cost has been paid, a commander must actively oversee the building of a fort for the number of turns specified. Note that this task can be passed between commanders, rather than being specific to the commander who began the construction. If no commander is currently ordered to construct the fort, the construction will maintain its current level of progress until a commander is given the order to continue. If a fort's initial construction is interrupted by an enemy army capturing the province, the gold cost is NOT refunded and all progress on the fort is lost. Note that building construction occurs after the ordinary movement+battle phase, so the province must remain in friendly control for the entire turn for construction to be completed.

Once they are built, forts may be upgraded to improve attributes such as wall integrity, admin value, and supply storage. Similar to initial fort construction, fort upgrades take a number of turns to complete. If an existing fort is besieged while it is being upgraded, the gold cost is still not refunded but progress on the upgrade remains as long as the fort is not lost.

A nation's summary screen will indicate what level and type of fort it is able to construct, albeit in a roundabout way. What "standard" forts means is dependent on the age. Nations that can construct "primitive" and "advanced" forts will be able to construct one tier lower or higher than what is standard, respectively. This is extremely significant where it means the nation gets one less CP per fort than the standard for their era (e.g. primitive default forts in the Early or Late Ages). EA Rus is a notable exception in that its "primitive" forts follow their own upgrade path entirely.

"Standard" max upgrade tier by age:

• Early Ages: tier two fort
• Middle Ages: tier three fort
• Late Ages: tier four fort

Commanders with the mason trait can upgrade a fortification to be one tier higher than what is usually available to their nation. For example, EA Arcoscephale's Engineers can upgrade Fortresses into Castles. This is particularly significant for nations which can upgrade to a fort with a +2 CP bonus, such as MA Ulm and MA Marignon. Helmut's Sappers, the mercenary company, comes with a mason commander.

Fort stats courtesy of the Dominions 5 Forts Spreadsheet.

If a nation has no modifier on their forts other than the usual primitive/standard/advanced, then they will follow the default fort upgrade path.

Image
Name	Palisades	Fortress2)	Castle3)	Citadel4)	Grand Citadel
Cost/Months	600/4	300/2	300/2	450/3	600/4
Admin	15	30	45	60	70
Com. Pt. Bonus	0	1	1	2	2
Rec. Pt. Bonus	50%	75%	100%	125%	150%
Supply Storage	100	500	1500	5000	7500
Base Defenders5)	1	2	3	4	5
Wall Integrity	100	250	500	750	1000

Fortified Cities are distinguished from the default upgrade path by their tier one fort providing +1 CP rather than having no CP bonus. This means that they are much more efficient than the default path if only built for the extra commander point. However, each tier of fortified city is more expensive to upgrade to and takes longer to construct.

The following nations can build fortified cities:

• All ages of Mictlan
• EA Ur and MA Uruk
• EA Mekone

The following nations start with a Fortified City, but any forts they build will follow the default upgrade path:

• All ages of Ermor
• MA Sceleria, LA Lemuria
• MA Pythium
• MA Phaeacia
• MA Ind

Image
Name	City Palisades	Walled City	Fortified City	Great Walled City6)
Cost/Months	750/5	450/3	450/3	600/4
Admin	30	40	50	60
Com. Pt. Bonus	1	1	1	2
Rec. Pt. Bonus	75%	100%	125%	150%
Supply Storage	500	1500	3000	7500
Base Defenders	1	2	3	4
Wall Integrity	100	200	300	500

Wooden Forts are available only to EA Rus. While these forts have very low stats compared to their tier-equivalents, they are also cheaper and faster to construct, and still provide the same +1 CP bonus at tier two.

Image
Name	Fortified Village	Wooden Fort
Cost/Months	450/3	300/2
Admin	15	20
Com. Pt. Bonus	0	1
Rec. Pt. Bonus	50%	75%
Supply Storage	150	200
Base Defenders	1	2
Wall Integrity	100	150

Giant Forts are available to giant nations. They cost more and take longer to upgrade to their second and third tier, meaning it requires more investment to get that crucial +1 CP bonus. In return, giant forts have more wall integrity than default forts.

The following nations can build giant forts:

• EA Formoria
• EA Niefelheim, MA Jotunheim, and LA Utgård
• EA Hinnom, MA Ashdod, and LA Gath
• MA Phlegra
• MA Na'ba

LA Phlegra starts with a Giant Citadel, but otherwise builds default forts.

Image
Name	Giant Palisades	Giant Fortress	Giant Castle	Giant Citadel
Cost/Months	600/4	450/3	450/3	450/3
Admin	15	30	45	60
Com. Pt. Bonus	0	1	1	2
Rec. Pt. Bonus	50%	75%	100%	125%
Supply Storage	100	500	1500	5000
Base Defenders	1	2	3	4
Wall Integrity	100	500	750	1000

Ice Forts are available only to MA Caelum and LA Atlantis, the latter of which can only build them on the coast. These are much cheaper than default forts and are faster to upgrade, but they "melt" and lose effectiveness in heat scales, and can only be built and upgraded in cold scales. If the temperature rises to neutral or above, construction is halted and can only continue once cold scales return.

For every temperature scale above 3, all stats of ice forts (with the exception of CP bonus and the base defenders multiplier) decrease by 10%. This means that ice forts take a 30% stat penalty at neutral temperature, and a 60% penalty in 3. If an ice fort spends enough turns in heat scales, it is permanently damaged and transforms into a Half-Melted Fort. In this state, the fort can only be restored by destroying it and building a new one in its place.

The stats in the table below are for ice forts in 3. The Half-Melted Fort's stats do not scale with temperature.

Image
Name	Ice Walls	Ice Fortress	Ice Castle	Ice Citadel	Half-Melted Fort
Cost/Months	600/4	200/2	200/2	300/3	-
Admin	15	30	45	60	2
Com. Pt. Bonus	0	1	1	2	0
Rec. Pt. Bonus	50%	75%	100%	125%	10%
Supply Storage	100	500	1500	5000	20
Base Defenders	1	2	3	4	0
Wall Integrity	100	250	500	750	10

While technically anyone can go underwater with enough investment, only a few nations that don't already start underwater can build forts there. Underwater forts are identical to default land forts in cost and stats, but take longer to initially construct.

In addition to all underwater nations, the following land nations can construct underwater forts:

• EA & MA Agartha
• MA & LA Xibalba
• LA Mictlan
• MA Shinuyama, LA Jomon
• EA Ur, MA Uruk
• LA Atlantis
• LA Erytheia

Citadels cannot be built underwater; the maximum rank available is the castle, resulting in a maximum CP bonus of +1. However, MA Ys starts with the Castle of Bronze and Crystal, which has the same stats as a citadel (including the +2 CP bonus).

Image
Name	Rock Walls	Fortress	Castle
Cost/Months	600/5	300/2	300/2
Admin	15	30	45
Com. Pt. Bonus	0	1	1
Rec. Pt. Bonus	50%	75%	100%
Supply Storage	100	500	1500
Base Defenders	1	2	3
Wall Integrity	100	250	500

These forts are specific to certain nations or produced by special sites. By their nature, they do not have a cost or time to construct.

Image
Name	Castle of Bronze and Crystal7)	City of Brass8)	Crystal Citadel9)
Admin	60	50	30
Com. Pt. Bonus	2	2	1
Rec. Pt. Bonus	125%	125%	75%
Supply Storage	5000	3000	500
Base Defenders	4	4	2
Wall Integrity	750	500	1000

There are a number of rituals that can construct a fort in a single turn during the magic phase. These ritual forts will land before any movement-phase attacks and are therefore capable of immediately preventing the province from being taken without a siege, making ritual forts critical to many a mid- to late game throne rush. Note that ritual forts cannot be cast on top of existing forts – the fort must be demolished before a ritual can be used to replace it.

Generic
Living Castle	Conjuration 7	41 • 40	Can only be cast underwater Range 4
	Fortress of Kelp and Coral: +1 CP, 400 Wall Integrity. One way for land nations to secure an underwater invasion.
Wizard's Tower	Alteration 8	4 • 50	Range 4
	Wizard's Tower: +1 CP, 1000 Wall Integrity. A strong throne rush or late game spam fort due to its grand citadel-tier wall integrity and relatively accessible path requirement. Rather expensive, however!
Three Red Seconds	Blood 8	5 • 120	Range 4
	Citadel of Power: +2 CP, 750 Wall Integrity. Notable for being the only ritual fort with a +2 CP bonus. Blood Nations that can't build citadels can demolish their capital fort and replace it with a Citadel of Power to increase cap mage production. 120 is also quite affordable compared to the 50 required to cast Wizard's Tower, at least for proper blood nations.
National
Grow Fortress	Alteration 0	4 • 35	EA Pangaea, MA Asphodel and all ages of Oceania Range 0, can only target forests or kelp forests10)
	Bramble Fort (land) or Kelp Fort (underwater): +1 CP, 150 Wall Integrity. Starting fort for EA Pangaea and EA and MA Oceania. Notably the only way for EA Pangaea, EA Oceania, and MA Asphodel to build +1 CP forts.
Fort of the Ancients	Alteration 5	4 • 35	MA and LA Pangaea Range 0, can only target forests or kelp forests
	Bramble Fort (land) or Kelp Fort (underwater): +1 CP, 150 Wall Integrity.

• Dominions 5 Forts Spreadsheet