領土可以花費
金錢通過各種基礎設施升級來提高 
產出和 
幸福度，以及提高其可訪問性和防禦性。投資基礎設施可以顯著提高一個國家的收入、
人力、
研究，通常情況下，人口越多的領土中效果越顯著。
建築
在領土中可以建造各種不同的建築可以提供各種local modifiers，比如提高人口 產出和 幸福度，調整人口中各階級的比例，推動
同化和
改信，增加
當地人口容量, 增加區域的
要塞和
港口等。領土可建造的建築取決於領土的級別，如 
定居點、
城市、
都會，其中一些 定居點建築會受到領土生產的貿易品的限制。
每座建築都有相應的 建築成本及 
建築時間，可由
gold cost 和
build time modifiers進行改變， 每個領土一次只能建造一座建築，但可以排隊建造多座建築。建築建造完成後，不需要支付任何維護費用。任何所擁有領土中的建築都可以隨時立即拆除，並將建築成本的1/4金錢返回國庫（受build cost modifiers的影響），無論建築是何時建成的或由誰建造的。一些事件和任務結果可能會在領土中自動建造一座建築。
共用
| 建築 | 省份效果 | 花費
|
時間
|
注釋 | |
|---|---|---|---|---|---|
 |
要塞 |
|
150 | 720 日 | 將領土的 堡壘等級提高 1 級。
請參閱 |
 |
港口 |
|
150 | 180 日 | 只能建在沿海地區  或遊戲開始時已經存在港口的地方。
將領土的 |
城市/都會建築限制
| 建築 | 省份效果 | 花費
|
時間
|
注釋 | |
|---|---|---|---|---|---|
 |
渡槽 |
|
150 | 180 日 |
需要至少 |
 |
穀倉 |
|
100 | 180 日 | |
 |
圖書館 |
|
100 | 180 日 | |
 |
市場 |
|
100 | 180 日 | |
 |
訓練營 |
|
100 | 180 日 | |
 |
稅務所 |
|
100 | 180 日 | |
 |
土壘 |
|
150 | 1440 日 | 每個領土只能建造一個。 Requires the  Fortified Camps  Martial inventionRequires at least 1 fort level.
|
 |
鑄造廠 |
|
300 | 180 日 | 每個領土只能建造一個。 Requires the Blacksmith Apprentices Martial invention.
|
 |
大神殿 |
|
300 | 360 日 | 每個領土只能建造一個。 Requires the Open Religion  Religious invention.
|
 |
大劇院 |
|
300 | 360 日 | 每個領土只能建造一個。 Requires Gradual Economic Integration  Oratory invention.
|
 |
學院 |
|
150 | 180 日 | 每個領土只能建造三個。 |
 |
法院 |
|
150 | 180 日 | 每個領土只能建造三個。 |
 |
廣場 |
|
150 | 180 日 | 每個領土只能建造三個。 |
 |
磨坊 |
|
150 | 180 日 | 每個領土只能建造三個。 |
定居點限制
| Building | Province modifiers | Cost
|
Time
|
Notes | |
|---|---|---|---|---|---|
 |
軍營 |
|
200 | 180 日 | 每個領土只能建造一個。 |
 |
礦井 |
|
200 | 730 日 | 每個領土只能建造一個。 |
 |
部落定居點 |
|
200 | 730 日 | 每個領土只能建造一個。 |
 |
奴隸莊園 |
|
200 | 730 日 | 每個領土只能建造一個。 |
 |
農業定居點 |
|
200 | 730 日 | 每個領土只能建造一個。 |
 |
Provincial Legation |
|
200 | 180 日 | 每個領土只能建造一個。 |
建築槽
格美領土中可建造的建築數量受限於該領土的
建築槽數量。每座建築占用一個槽位，包括正在建造中的建築，在已填滿所有槽位的領土上無法建造更多建築。擁有超出允許槽位數量的建築的領土（例如，在被掠奪期間失去人口後）將失去超出限制的建築。 
奇觀也占用一個建築槽位，並且至少需要一個空的建築槽位才能開始建造。
定居點通常只有1個建築槽位（儘管定居點建築一般比其他建築更強大），可以通過使用 革新進行 
發明 鄉村規劃改變global settlement building slots modifier 增加至最多2個（儘管每座定居建築仍將保持其領土上限為一）。建築槽位在定居點升級為 城市時變得更加重要，城市可額外獲得2個建築槽位，並且每增加10 
人口可額外獲得1個建築槽。如果城市進一步升級為 都會，則額外建築槽位數量增加至4個。在 城市和 都會中的建築槽來源於 local city building slots and global city building slots modifier，包括以下：
- +1
國家首都 - +1
聖地 - +1 for all cities with a tier 3 wonder with the
Engineering effect - +2 for all cities with a tier 4 wonder with the Engineering effect
- +2 for all cities with the Urban Planning Civic invention
- +1 for all cities with the
Legacy of the Builders military tradition (Levantine and Arabian traditions) - +1 for each
Make Religious Endowments religious province investment
奇觀
- 主條目：Great wonders
Great wonders are special buildings that can be constructed in territories and give powerful bonuses to their local province or owner. Unlike standard buildings, wonders can be customized with various designs, materials, and effects, and are a significant investment that only the large and wealthy empires will be able to afford. As the centerpiece and defining feature of the local area, each territory can normally only support one great wonder, though certain wonders that are built by event can coexist with each other in the same territory. Uniquely, wonders usually give strong nation-wide effects that grow over time as the wonder's fame and prestige increases.
At the start of the game, there are a number of ancient wonders scattered all over the map, from the Temple of Jupiter Optimus Maximus in Rome to the Great Pyramids of Giza and the University of Taxila. Building additional wonders requires the Heirs of Alexander DLC.
道路
Roads can be built by 
armies to connect two adjacent territories at the cost of gold, reducing the 
movement cost by 50% and effectively doubling the army movement speed between them, making them highly desirable for larger empires that would benefit from being able to move armies between their provinces more quickly. In addition to the army movement bonuses, connecting a territory to the road network also gives a minor boost to development, trade, and pop mobility, making them useful to build in highly populated developed territories as well as connecting frontier areas. Roads also appear graphically on the map as the network is built and extended, generally being most prominent on the terrain mapmode; if a road is built over a river, a bridge will appear. Unlike with buildings, roads are not associated with individual territories, but instead with pairs of adjacent territories (including possibly those connected over a strait); it is therefore possible (and common) for a territory to be a part of multiple different road segments. For every road connecting a territory to one of its adjacent territories, a territory will get the following stackable modifiers:
+0.001% 本地文明度變化- +2.5% 人口改信速度
- +2.5% 人口同化速度
+2.5% Pop Promotion Speed
+1% Pop Demotion Speed
+0.05 移民吸引力
+0.1 人口移民速度
+5% 當地基礎貿易路線 Modifier
There are two ways to build roads - a special, cheaper method for countries with access to Italic tradition groups, and more generic one that is available to all countries. Once a road is built, it cannot be removed or destroyed, even if the territories it connects are completely depopulated.
Regular roads
Most countries need to reach at least 
Level 5 of civic advances to begin building roads.
Roads can be built using the 
Build Road unit ability toggle, which can be activated if all of the following conditions are met:
- The unit is an army
- The army has at least 10 cohorts
- The army is not in combat, moving, or exiled
- The army is in a territory that is owned by the current country, or by one of its
subjects - The army either has no commander, or its commander is loyal (i.e. has at least
34 loyalty)
Any type of army, even 
levies and 
mercenaries, can build roads, if they meet all of the requirements.
When the build road toggle is on, road construction will begin when the unit moves from one territory to another, as long as both territories either owned and controlled by the army's owner or one of their subjects, or are uncolonized (including uninhabitable territories, though not impassable terrain). When the army arrives in that other territory, if the two territories do not already have a road between them, the road will be instantly built at a base cost of 50 gold. This cost is affected by the build roads cost modifier, given only by the Civic inventions Gromatici ( -25%) and De Architectura ( -15%). If the army has at least 
1 engineer cohort, the cost of building a road is instead lowered to to 10 gold (not affected by any modifiers).
While building roads, the following modifiers are applied to the army:
−25% 陸軍士氣
−70% 陸軍無道路移動
+120% 軍團維護費
The toggle will be turned off if the army becomes ineligible to build roads, or if the army finishes moving to a new territory without a road on the traversed connection and the country does not have enough money to build a road.
軍用道路
If a country has access to Roman traditions (in the Italic traditions group), adopting the Roman Roads tradition will give access to the special Build Military Road toggle, even if it does not currently meet the technology requirements for building roads normally. Building military roads is largely the same as building regular roads, with the main differences that the road-building army can be smaller, requiring only 5 cohorts, but must be a 
legion, and that each road costs only 25 gold per territory connection. However, note that the cost is not affected by the build roads cost modifier. As with normal road building, the cost is lowered to to 10 gold (also not affected by any modifiers) if the army has at least 1 engineer cohort.
In addition, a reduced set of modifiers is applied to the road-building army, without the increased maintenance cost or morale penalty:
- −70% 陸軍無道路移動
要塞
- 參見：Siege
Forts can be built in territories to block the advance of enemy armies and protect important cities and strategic points from being easily captured. The size of a fort is determined by its fort level, where 1 is the minimum and 0 indicates the lack of a fort, and every 
fortress building giving 1 fort level. This means that settlements are typically restricted to a fort level of 1, while cities and metropolises are able to support larger forts. The higher the fort level, the harder it is for an enemy army to successfully take the fort.
To fully occupy a province, the attacker must besiege its 
capital and any forts in the province, after which the rest will be automatically occupied after a few 日. An unprotected territory takes only 15 日 to occupy, while one with a fort will take multiple months to siege down unless the attacking army launches an 
assault (usually taking heavy casualties). Each fort level gives -1 to siege progress and provides the base 
garrison of 500 per fort level, adjusted by the garrison size modifier. A besieging army needs to have at least 2000 men per each fort level to begin a siege, no matter how big the garrison is. Assaulting a fort will damage the garrison, and as soon as it reaches 0, the fort will fall. When it falls (or a new fort level is built), its garrison will start replenishing at a rate of 10% of the max garrison per month.
In addition, forts exert a zone of control (ZoC) over adjacent territories. An army that enters a hostile zone of control will not be able to progress further, and must either proceed to the fort and besiege it or return to the territory they came from. 
蠻族 ignore all zones of control and can move freely, but territories in the zone of control of a friendly fort will not lose 文明度等級 if occupied. Friendly forts also negate 
attrition from deserts or winter, and will automatically occupy any enemy-controlled territories in its zone of control unless there is a hostile army there.
Every fort level costs a base of 0.40 gold in maintenance each month, adjusted by the 
fort maintenance modifier, except for the first capital fort.
Every province has a certain fort infrastructure capacity value, with default capacity of 5. The first fort in a territory uses up 3 points of capacity, while subsequent fort levels only use 1, and exceeding the limit gives a +25% maintenance modifier for all forts in the province by for every point over the limit. This means, with the default limit of 5, two level 1 forts in one province would use 6 points and cost [math]\displaystyle{ 0.4*1.25 = 0.5 }[/math] each per month in maintenance ( 1 in total), while a single level 2 fort costs 0.8 gold per month to maintain. Capacity can be increased through the 
Fortify Province province investment, several military traditions, some inventions, and a wonder effect.
Every territory in the province gets 
-0.25 unrest for every used fort infrastructure point, which means spreading forts out over a number of territories is much more efficient at suppressing unrest than concentrating them in a single territory, even if more expensive. As maintaining forts can be costly, it is often a good idea to remove extraneous forts that no longer serve any meaningful defensive and unrest-suppressing purpose.
邊境要塞
- 參見：Colonization
A country that has adopted the Castra military tradition from the Italic tribe traditions tree can have an army build a 
border fort in an owned frontier or neighbouring uncolonized territory. An army can do this action if it meets all the following conditions:
- The unit is an army
- The army has a loyal commander (defined as 34 loyalty or higher).
- The army is not in combat, moving, sieging, or exiled.
- The army has at least 5 cohorts, including at least one that is not
loyal to anyone. (This requirement implictly means that mercenaries cannot be used) - The territory the army is in:
- Doesn't already have a fortress
- Is uncolonized, or owned by the current country and borders a foreign (not uncolonized) territory
- Has a free building slot
- Borders an owned and controlled territory
- Is not next to any other owned territory with a fortress
- Doesn't already have a
When the ability is activated, the country loses 3000 manpower and builds a fortress in the territory. The country then gains ownership of the province if it was previously uncolonized, in which case the territory will also gain a 
freeman pop of the primary culture and religion. Finally, one random cohort becomes loyal to the commander, unless the general is the ruler of a non-republic, in which case the country gains 
1 tyranny instead. This ability can notably be used to colonize territories even if there is no neighbouring territory with a dominant integrated culture and state religion.
港口
Ports are buildings that can be built in any coastal territories, as well as certain inland territories on 
major rivers (those that begin the game with a port). They allow 
ships to dock (including quickly embarking and disembarking troops), be built, repair, and supply, and are important for any nation that seeks to maintain a significant navy. The number of ports in a territory is the territory's port level, which in addition to the effects from the port buildings themselves also determines what types of ships it can build and repair: the light 
liburnians and 
triremes only require a level 1 port, the medium 
tetreres and 
hexeres require at least level 3 ports, while the very heavy 
octeres and 
mega-polyremes can only be built and repaired at ports that are at least level 5.
In addition to effects from the building itself, every coastal territory with at least one port gets the following modifiers:
+5% Supply Limit- +10% Pop Promotion Speed
For each territory in a province that has at least one port, the province also gets the following modifier:
- +2.5% 人口移民速度
Note that neither of these effects stack if territory has more than one port.
Pirate havens
Certain ports are home to 
pirate havens where groups of pirates are based from. These pirate havens are present in certain ports at the beginning of the game, and in addition to giving an economic boost of 
+20% local tax and 
+0.01% Local Population Growth to their territory they host pirate fleets, always composed of all light ships, which can rented out as naval mercenaries at times of war. When not being hired pirate fleets will eventually grow restless and go on raids, at which point the fleet while become hostile to all other navies and travel to nearby unfortified ports to plunder them, giving -25% local tax and +10% Demotion Speed to the plundered territories.
If pirates grow to be too much of a problem, their havens can be destroyed using the 
Root Out Pirates army ability on any controlled territory once the anti-pirate law has been passed, including those belonging to other countries that have been occupied in a 
war. This will remove the modifier (including its beneficial modifiers) and destroy the associated pirate fleet, even if it is currently out on a raid. Alternatively, pirates can be actively encouraged by passing the pro-pirate law, which will create a new pirate haven in one of the country's ports to increase its prosperity and provide more available naval mercenaries at the expense of the nearby coasts.
Destroying all ports in a pirate haven will also force any local pirate/mercenary fleets to disband, though this will not remove the pirate haven itself. If the port is ever rebuilt, the pirate fleet will eventually reappear.