殖民是将无主地转化为殖民地的过程。它可以为任何希望成为列强的国家提供一些重要的好处：
《黑暗之心》中的殖民
在《黑暗之心》扩展包中，殖民是一项颇为复杂的内容。为了增长成为殖民帝国的潜力，你的国家需要一支强大的海军和正确的科技，使得你能够扩张到那些不适宜居住的地区。
机制
殖民分为三个步骤。
探险
要殖民一个省份，该省份必须在你的国家所能及的范围内，并达到或超过你的国家的最低生活条件。只要目标省份离最近的海军基地足够近，或者与一个已经被控制的省份相邻，目标省份就在殖民范围之内（毗邻一个卫星国也计入）。一个国家的最低生活条件受到其发现的科技的影响。
派遣一支探险队需要消耗100点殖民力量，但如果目标省份毗邻一个已经被控制的省份，则只需要80点。
探险队派出后，必须等待一段时间才能对殖民地作出下一步行动。如果没有其他国家在该地区进行殖民行动，殖民地可以直接变成保护国，只需付出一点点额外的殖民力量成本。然而，如果其他国家加入了竞争，这就变成了一场竞赛，两个国家将不断升级他们的远征队，直到其中一方从竞赛中撤出他们的殖民力量并承认失败。
如果一场殖民竞赛持续太久，它最终将引发一场危机。要想知道这场竞赛有多接近危机，请查看地区视图上的彩色进度条。
殖民省份/保护国
当一个列强或次强的远征队没有受到另一个国家的竞争（可能是因为所有其他竞争对手都退出了），或者当一个国家比最近的竞争对手多投资了三个等级的远征队时，就可以建立保护国。
殖民地的维持成本比保护国高，但它们为国家提供了更多的税收，并且国家可以从中征召军队。然而，工厂不能在殖民地建造。
当一个开化国家通过“索要租借地”或“建立保护国”（尽管名称如此，后者实际上创造了殖民地）的宣战理由从未开化国家征服了一个地区时，也会产生殖民地。注意，即使目标地区已经是获得它的国家的核心，它仍然会变成殖民地而不是本土（这种情况很少见，比如
South Africa收复他们在
Zulu的核心时）。
开化国家可以通过“阳光下的土地”的宣战理由从另一个国家夺取殖民地。
州
将殖民地转变为成熟的州需要在殖民地拥有至少1%的已接受文化
官僚人口。转变为州需要消耗殖民力量（游戏中显示如此，但是实际上州不会占用任何殖民力量，因此它只是要求你的可用殖民力量达到一定数量，而不会实际消耗任何殖民力量，反而还会因不再有殖民地而增加殖民力量）。
殖民力量
殖民力量可以通过如下途径获得：
- +100来自“后纳尔逊时代军事思想”科技。这项加成通常作为所有列强、次强的基础殖民力量。
- +30来自每个在核心领土上建造的海军基地
- +20来自每个在核心领土上升级的海军基地额外等级
- 海军中的战斗舰只（如果海军数量超过了补给上限，超出部分的舰只会减少殖民力量）：
| 级别 | 殖民力量 | 补给需求 | 每1点补给需求 产生的殖民力量 |
|---|---|---|---|
| 护卫舰 | 2 | 1 | 2 |
| 风帆战列舰 | 5 | 2 | 2.5 |
| 破交舰 | 8 | 3 | 2.6 |
| 铁甲舰 | 12 | 3 | 4 |
| 低舷铁甲舰 | 10 | 3 | 3.3 |
| 巡洋舰 | 16 | 20 | 0.8 |
| 战列舰 | 15 | 50 | 0.3 |
| 无畏舰 | 22 | 60 | 0.36 |
护卫舰、风帆战列舰和破交舰可以用于在早期游戏中获取殖民力量，但应当在情况允许时转变为更有效率的铁甲舰或低舷铁甲舰。铁甲舰是最有效率的舰种，每1点补给需求产生4点殖民力量。但是，铁甲舰相当昂贵，建造时间也长，并且不能在海外建造。因此，它们只适用于那些拥有许多本土海军基地和充足的准备时间的国家。那些本土海军基地很少或准备时间不足的国家应该把重点放在建造低舷铁甲舰上。
巡洋舰、战列舰和无畏舰的出现时间太晚了，对殖民竞赛帮助不大，而且也是迄今为止效率最低的舰种。
殖民力量用于在殖民竞赛中投资，以及将保护国转变为殖民地。如果一个国家有足够的可用殖民力量，并且一个殖民地满足转变为州的条件，那么他们就可以把该殖民地并入自己的国家。这将释放更多的殖民力量，允许他们发展新的殖民地。
然而，整合一个殖民地所需的可用殖民力量随着距离的增加而增加，甚至可以轻易地超过一个伟大帝国的潜在殖民力量。如果一个国家希望殖民更多的土地，他们可以释放一个相邻的殖民地成为自治领。这可以通过“政治”界面上的“释放”选项卡来完成，与释放卫星国的方式相同。
生活条件与科技
所有国家在游戏开始时的最低生活条件都是35。虽然有几个地区可以在游戏早期就殖民，但大多数潜在的殖民地并不是那么宜居。
有三项发明可以降低一个国家的最低生活条件。他们是：
疟疾预防药物在研究药品后每月有2%的概率被发现，降低5点最低生活条件。
开化使命和殖民谈判的条件更为复杂：它们的发现概率并不取决于自身的前提科技，而是由任意列强或邻国拥有此发明而增加10%，和该国拥有某项更为后期的科技而增加25%。
具体来说，开化使命需要三项1850年开启的科技之一：
而殖民谈判需要三项1870年开启的科技之一：
研究任何一种后期科技所带来增益，都超过了列强和邻国已经拥有这项科技的增益之和。
一般来说，如果玩家是第一个获得殖民谈判的玩家，并因此能够殖民，其他大国将很快由邻国增益或列强增益而跟进。这导致了19世纪70年代的殖民热潮，尤其是在非洲，那里大多数空旷的省份的生命等级都是10或15（历史上，对非洲的争夺始于1881年）。任何一个在1880年之前还没有研究后膛枪的国家都可能会错过机会，发现整个非洲都已经被殖民了。
Strategy
Early colonization (before 1870)
A handful of provinces have life rating 35 and so their states can be colonized in 1836:
- Alberta and British Columbia: Occasionally the
USA grabs the parts of BC that the 
United Kingdom doesn't already have, but otherwise only the United Kingdom is in a position to colonize them, and almost always does so. - Oklahoma, Colorado, Oregon and Washington: These are contested between the USA and
Mexico. They often go to war over them (when the USA takes the "Manifest Destiny" decision giving them cores on all of the continental US), and the USA usually wins. - Sakhalin: An island north of
Japan. Both 
Russia and Japan have cores, but Japan starts uncivilized and so can't colonize for at least a couple of decades, leaving Russia free to grab it after building a Pacific naval base. - Turkmenia: Initially inaccessible to any power, Russia can colonize by conquering Khivan Uzbekia; the Ottomans would have to conquer two states from Persia.
- Bornu: Being in the interior of west Africa, colonizing this requires conquering part of
Sokoto. This is a strategically important location that can give the player a big advantage during later colonization. - Lourenço Marques, Zambezia (not to be confused with Zambezi) and Mocambique (sic): Inaccessible to anyone but Portugal, they will start colonizing these from day 1.
- South Madagascar:
Portugal and 
France can try for Comoros and Mayotte (despite the state name these islands are north of Madagascar), and the United Kingdom can build a naval base in the Seychelles or Mauritius; anyone else probably won't have range.
A few more have life rating 30 and can be colonized with only Prophylaxis against Malaria. With luck, a quickly westernizing uncivilized country may be able to take some of these, but they are still mostly restricted to an exclusive club.
- Manitoba and Saskatchewan: Only the United Kingdom has access here, unless the USA manages to seize BC.
- Alor, Sunda Islands: Bordering the Netherlands' and Portugal's colonial possessions in Indonesia, this can also be picked up by
Spain. The United Kingdom will have to build a naval base first. - Darfur: Even the AI will conquer Dongola from
Egypt to get access to both this and a coastal province for a port. Only Fasher in the south has life rating 30, but this allows colonizing the entire state. - Amhara and Oromia: These states border (and are partially owned by) Ethiopia, who can get them immediately if they somehow become a secondary power in time; anyone else will have to conquer land from Ethiopia.
- South Georgia: Usually taken by the United Kingdom, this island, historically only ever used as a whaling station and never permanently inhabited, can also be taken by
Brazil or 
Argentina if they become a secondary power at the right time. - South Island and North Island, New Zealand: Only the United Kingdom has anywhere near the range to get these.
The following can be colonized from 1850, once the country has Mission to Civilize:
- East Angola and South Angola: More African states that only Portugal will have access to. These are also the only provinces that can be colonized with only Mission to Civilize and without Prophylaxis against Malaria, but you will want Medicine anyway.
- Interior of Australia: In 1836 the United Kingdom has already colonized the entire coast of Australia, so only they get access here.
- Northwest Territories: Part of Canada, only the United Kingdom is likely to have access.
- Etorofu and Shumshu (the Kuril Islands): Like Sakhalin, both Japan and Russia have cores here; unlike Sakhalin, Japan stands a chance of colonizing them if they're quick to westernize and get colonization tech.
The Scramble for Africa (1870s)
All other uncolonized provinces, including almost all of Africa, have life rating 15 or 10 and can only be colonized with both Mission to Civilize and Colonial Negotiations. Since most powers who have researched Breech-Loaded Rifles get Colonial Negotiations at almost the same time, there is a rush of colonization activity soon after any great power has discovered it. Those with life rating 10 also require Prophylaxis against Malaria, but any savvy power will have it anyway. A more in depth guide can be read here: Guide for Scramble of Africa
In the base game and in A House Divided
Mechanics
To colonize an uncolonized area, the following requirements must be met:
- Have a country status of at least secondary power (i.e. civilized and rank 16 or better);
- A naval base in range OR share a land border with the target colony;
- Have the technology to tolerate the life-rating of the area.
All nations start with a life-rating minimum of 35. Most colonial areas only have a life-rating of 15. However, you can lower your minimum allowed life-rating through research:
- Industry tech: Prophylaxis Against Malaria (Medicine) (1836)
- Culture tech: Nationalism & Imperialism (1850)
- Army tech: Machine Guns (1870)
Once all the requirements are met, select the "Colonize" national focus on your target to began the colonization process. Since most uncolonized areas are out of reach until both Machine Guns and Nationalism & Imperialism are researched, large scale colonization will not begin until 1870 at least. However for a colonial power to succeed, it would be important to prepare naval bases and rack up focus points in the years prior.
Conversion to a full state
To convert a colony to a full state it is necessary to have 1% bureaucrats in the colony state in your accepted culture. In general, having this number of bureaucrats is achievable once an acceptable culture makes up approximately 5% of the population of the colony. There is a greyed out button next to the national focus icon that tells you your progress, when that number is reached, you may press the button to convert the colony into a state. A colony may only be converted to a state when you are not at war. Note that due to these requirements, the vast majority of colonies in the game will never be able to convert to states.
Factories can only be created in states, so creating states can help a country's industry.