Pops - that is, your people - aren't static entities in Victoria 3. They have wants, needs, and visions of their own - sometimes, this will force them to move about, either within your borders or further afield, if they feel the need.
Migration is the term that Victoria 3 uses for the movement of Pops within the same market - note that in the case of overlords and vassals, and customs unions, this may be between different countries. Pops will want to migrate if their Standards of Living are too low, and can be restricted and affected by infrastructure and laws.
Migration Laws
How able your Pops are to migrate is dictated by your laws. You'll find Migration Laws under the Human Rights header in the laws menu, and there are three options to choose from:
- No Migration Controls means that any Pop can migrate when they feel it's necessary.
- Migration Controls is a little stricter and restricts any discriminated Pop from migrating. Discriminated Pops are those that have cultures or religions that aren't accepted by your country.
- Closed Borders completely halts migration, both internally and externally.
If enabled, migration will happen over time, with the flow of Pops being dictated by levels of Migration Attraction - they will move from states with low Migration Attraction to states with higher Migration Attraction.
Migration Attraction
Migration Attraction is a measure of how attractive a state is to move to, live in, and work in. The main factor in Migration Attraction is the average Standard of Living in a state, which is very important for multiple reasons. The higher the Standard of Living, the more people will want to live there - makes sense, really.
There are some things that will severely reduce Migration Attraction, though they are less permanent than Standard of Living:
- Devastation after a war.
- Turmoil thanks to Radicalism.
- High levels of unemployment.
Dealing with these problems will raise Migration Attraction. There are also other ways to improve Migration Attraction:
- The Greener Grass Decree can be set to a state for an easy bonus to Migration Attraction.
- The Colonial Resettlement Law will give a massive bonus to Unincorporated States, which should prevent or reduce migration when you take a new state.
- Trade Centers get a bonus, as does being a Market Capital.
Migration Targets And Emigration
While migration occurs within a market, emigration means Pops are leaving a country, taking their money and working power with them. Emigration only occurs due to Cultural Turmoil.
Cultural Turmoil is generated by Pops of a certain culture who are displeased with the country they live in. It is a global measure that tracks the Turmoil of every single Pop of that culture, not just the Pops within a certain nation.
If the global Cultural Turmoil of a culture is high enough, the game may select a Migration Target for that culture, and Pops of that culture will start mass-migrating to that area from all over the world, if applicable.
There is not much you can do to prevent Cultural Turmoil and emigration, as the most likely candidates for emigration are cultures spread out over many countries, and you have little to no input in the Turmoil levels in other countries.