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Individual colonies will naturally grow on their own each month. Their growth rate depends on several factors:
- Global Settler Increase
- Colonist’s Settler Chance
- Native Assimilation
- Province Climate (Arid, Arctic, or Tropical)
If you wish to rapidly spread throughout the New World and the Indies, consider acquiring multiple colonists and modifiers to your global settler increase stat.
Most of them are available in the Exploration and the Expansion idea groups.
A colonist is a type of envoy that you’ll use to establish colonies. The two colonization-focused idea groups can give you three colonists:
- One from Exploration
- Two from Expansion
You get your first idea group slot at Admin Tech 5 and another slot at Admin Tech 7.
It’s recommended that you choose Exploration first.
It lets you recruit explorers and conquistadors, which you’ll need to discover uncolonized areas. It also expands your colonial range, allowing your colonists to reach more distant lands.
Both Exploration and Expansion also unlock random events that give benefits to your colonies.
Certain nations also come with one additional colonist from their national idea set:
|Nation||Status at the 1444 Start|
|Asturias||Releasable by Castille|
|Leon||Releasable by Castille|
|Nizhny Novgorod||Releasable by Muscovy|
Colonists have an envoy travel time when you send them out to colonize. It may take them weeks or even years to reach their destination depending on its distance from your capital.
Tip: You can get modifiers that reduce envoy travel time from the Influence (-25%) and the Exploration (-20%) idea groups.
When a colonist gets recalled or has finished turning a colony into a city, they’ll be available again after just one day.
Once you have your first colonist, you’ll need to set your native policy before you can start colonizing.
You have three options:
- Native Coexistence: -100% native uprising chance
- Native Trading: -50% native uprising chance and +50% native assimilation
- Native Repression: +20 settler growth
The first time you do this is free. Switching policies later will incur a -1 hit to your stability.
Tip: Completing both Expansion and Exploration will unlock the “Colonial Expansion” diplomatic policy. This gives you +20 settler growth and -50% native uprising chance. Pairing this with the “Native Trading” policy is better than using “Native Coexistence”.
Native Population and Assimilation
Except for desert islands, uncolonized provinces usually have native inhabitants.
There’s a monthly chance that they’ll attack your colony. This probability can be mitigated or fully negated by your native uprising chance modifier.
If natives attack and successfully occupy your colony, they’ll reduce its population by -100 per native regiment.
Should a colony’s population drop to zero, it’ll be destroyed and you’ll have to reestablish it again.
You can check a province’s native population size in the Uncolonized Land UI.
- The population size determines how large an uprising you’ll potentially face
- Each ax icon of aggressiveness is equal to a 1% monthly uprising chance
- Each bow icon of ferocity gives 0.2% military tactics bonus to the natives
You can order an army to “Attack Natives”. Doing this repeatedly can wipe out the native population, eliminating any chance of an uprising.
However, this should only be done if you don’t have the resources to station troops in your colonies.
It’s better to tolerate the natives and allow them to remain with your colony as it grows. You may get random events where some of the natives will become settlers in your colony.
Furthermore, once a colony becomes a city, its natives will get assimilated. The city can get a goods produced bonus based on its native population:
Native Assimilation Bonus = Native Population ÷ 20000
For example, a colony with 3000 natives can produce 0.15 more goods per month once it becomes a city.
You can further increase that bonus with these modifiers:
|Name||Type||Native Assimilation Modifier|
|Native Assimilation Act||
(Expansion + Humanist)
|Establish New World Missions||Clergy Privilege||+50%|
|Native Trading Policy||Native Policy||+50%|
Global Settler Increase
Colonies receive new settlers each month. Once they reach 1000 settlers, that colony will become a city.
The number of immigrants colonies get per month is based on your yearly global settler increase. You gain additive increments to that from your Diplomatic Tech Level:
|Diplomatic Tech Level||Global Settler Increase|
Civilized nations start at Diplomatic Tech 3, which means a +25 global settler increase.
If you want to stay competitive with other colonizers (like Portugal), you’ll want to actively get more modifiers to your global settler increase stat.
Here’re the ones accessible to most nations:
|Modifier Name||Modifier Type||Yearly Settler Increase|
|Grant New World Charters||Burgher Privilege||+10|
(Micronesia, Southwest Pacific)
|Trading in Cotton||Strategic Trade Good||+20|
|Native Repression||Native Policy||+20|
(Expansion + Exploration)
The Colonial Administration Act
(Administrative + Exploration)
The Colonial Companies Act
(Exploration + Plutocratic)
Native Assimilation Act
(Humanist + Exploration)
(Quantity + Expansion)
|Faster Colonists||Expansion Idea||+20|
|Land of Opportunity||Exploration Idea||+10|
Note: Colonies that aren’t adjacent to any of your existing cities will have a -5 penalty. Provinces in arid, arctic, or tropical climates will further receive a -10 malus.
Your colonies also have a monthly chance of attracting 25 extra settlers. This settler chance is only active in colonies with an assigned colonist.
All colonies have a base chance of 10%. This is further modified by:
|Colony Population||-1% per 100 settlers|
|Native Aggressiveness||-0.5% per point|
|National Production Efficiency||+0.2% per point|
|Colony and Capital Are in the Same Continent||+5%|
|Colony Has Your State Religion||+1%|
|Colony Has Your Primary Culture||+1%|
|Colony Is in Your Culture Group||+1%|
“General Colonization Law”
(Expansion Idea #6)
“The Pioneer Policy”
(Expansion + Offensive)
(Exploration + Innovative)
“The Colonial Administration Act”
(Exploration + Administrative)
|“Steppe Nomad Migrations”
(Exploration + Horde)
Each colony costs 2 ducats per month. If you’ve more colonies than colonists, you’ll pay a premium on top of the regular 2-ducat cost.
The exact formula is:
Overhead per Additional Colony = 2 ⋅ x²
x is the number of extra colonies beyond your colonist count.
For example, if you have 5 colonies but only 3 colonists, your 4th colony will cost 4 ducats, and your 5th at 10 ducats.
You can check your colonial maintenance expenses in the Economy tab.
Tip: Recalling colonists and then sending them to establish new colonies elsewhere can be a good strategy for rapid expansion, as long as you can cover the increasing costs.
You’ll automatically form a colonial nation if:
- You’ve built 5 cities in a colonial region
- Your capital isn’t in the same subcontinent as those 5 cities
Note: Territorial cores are enough to form colonial nations. Turning cities into full state cores is a waste of Admin mana.
These are the predetermined colonial regions:
Note: Each nation can only have one colonial nation per colonial region. Any newly acquired or built province in these regions will automatically be transferred to your colonial nation.
A colonial nation is a special type of subject that doesn’t take up a diplomatic slot. They come in three designations:
|Designation||Modifiers to Subject|
|Private Enterprise Colony||
Of these three, Self-Governing Colonies are best at expanding through uncolonized land because they get an additional colonist.
Their +25% Liberty Desire can be offset by:
- Lowering their tariffs
- Taking the Influence idea group
- Granting the “Strong Duchies” privilege to your Noble estate
- Improving relations with them
You can change your colonial nation’s designation at any time in the Subjects tab. This costs 1000 ducats.
Subsidizing Your Subject
Your colonial nation will usually take Expansion for either their first or second idea slot. However, they won’t immediately use their colonists.
They’ll typically focus on their economy first. The AI won’t establish colonies unless it has money to cover the colonial maintenance costs.
You can help them by giving them subsidies. You do this from the Economic actions in the Diplomatic tab.
Winning the Treaty of Tordesillas
Historically, the Treaty of Tordesillas was an agreement between Portugal and Spain. Everything east of the Tordesillas meridian goes to Portugal, while everything west goes to Spain.
In EU4, the Pope awards the treaty to whoever first establishes 5 cities in a colonial region.
The awardee’s current and future colonies in that region will get +10 settler increase. This is also granted to your colonial nation. Meanwhile, foreign colonies will have a -20 settler increase penalty.
Each colonial region will have its own treaty winner.
One advantage from being the awardee is that other nations will usually give up on expanding in regions with a treaty winner.
A violator of the treaty will get a penalty to relations with the awardee and the Pope.
Defending Against Native Nations
Native tribes that neighbor you or your colonial subject have the “Push Back the Colonizers” casus belli.
This is a special CB which allows natives to directly attack a colonial nation without involving their overlord.
This can be dangerous in North America, where most native tribes will form large federations.
If your colonial nation does get attacked, you’ll need to use the “Enforce Peace” diplomatic action on the attacker.
They’ll most likely refuse, but that allows you to join the war and defend your subject.
When you win the war, you can fully annex the tribal lands of your enemy. This doesn’t cost any mana, and the lands will automatically be transferred to your colonial nation.