- See also: List of states
The state is the primary geographic unit of Hearts of Iron 4. A state consists of a set of provinces. In turn, supply areas, strategic regions, and the territory of countries consist of a set of states.
- Main article: Diplomacy
Ownership over territory is determined at the state level. Control over both the resources and state-wide construction of a state is determined by the plurality controller of a state; meaning the country that controls the most victory points. Each province in a state is worth 0.1 victory points but some provinces (usually cities) have additional victory points. These are all named and marked with small squares (1 to 15 VPs), circles (20 to 40 VPs), or stars (capitals with 3 to 50 VPs) on the map and their additional victory points are shown through the tooltip when hovering over them. Resistance is also computed at the state level.
States can be either core states or colony states. Cores are considered an integral part of the country, and the inhabitants are fully available for military service. Nations get a -98% penalty to manpower in colony states, and also only have half as many building slots available as in a core state. Nations may justify war goals against foreign-owned core states in half the time and for half the political power as on other states. Additionally, only victory points in core states count when determining if a country will capitulate. When a nation controls a non-core state, that state will generate resistance.
Unlike other Paradox games, there is normally no way for countries to gain cores. You can lose cores if you release/return territory of a country. However, some country-specific events and national focuses, like the Anschluss event for Germany or decisions for Mexico for central America, will grant cores. However, as of the La Resistance expansion, there is an exception to this rule, with Anarchist Spain able to core any state with enough compliance with the Global Defense Council focus.
- Main article: Construction
Construction can be divided into three categories: state buildings, shared buildings and province buildings.
State buildings are state-wide and every state may get the same maximum level of a certain building.
Infrastructure, airbases, anti-air and radar stations belong to this category.
Shared buildings are also state-wide, but the amount that can be built is limited to the number of free slots. Once all slots are occupied, no more shared buildings can be built.
Factories, dockyards, synthetic refineries, fuel silos, rocket sites, and nuclear reactors belong to this category
Province buildings are built per-province, their maximum levels depend on the type of building.
Naval bases and forts belong to this category.
- Main article: Production#Resources
Resources for production are generated at the state level. The majority controller will have a certain amount of the resources of a state added to their resource pool depending on their occupation policy.
The population in a state is tracked by five numbers.
The total population is the population the state starts with; it is shown on the state's info panel. Monthly population growth is based on it and the total never declines. The game's duration usually spans less than a generation, so all inhabitants that could enter military service are already born at the start of the game.
The recruitable population is available for the controlling country to use in military service. Recruitable population gets reduced as manpower is used in the military, not just after taking casualties.
The recruitable population cap is a fraction of the total population that limits the recruitable population. For how the fraction is calculated, see recruitable population.
The civilian population is the portion of the population that is not available for military service.
The civilian population cap is a fraction of the total population that limits the civilian population. It is the total population minus the recruitable population cap.
Changes in the effective recruitable population ratio can cause one of the two population counts to overflow. In this case population is transferred to the other population type. For example, if a country raises its recruitment law, the civilian population cap will go down over time (according to the mobilization speed), which causes some civilian population to be transferred to recruitable population. Conversely, if a state is captured by a country that does not have a core on it, the recruitable ratio will be massively reduced and might cause recruitable population to transfer back to civilian population.
The state's total population grows by +0.125% at the start of every month. The increase in population is distributed between recruitable and the civilian population by the recruitable ratio. Both increases are always at least one person respectively.
- Main article: Occupation
The effects of occupation, including resistance, are computed at the state level.
The monthly population growth of a state is NCountry.POPULATION_YEARLY_GROWTH_BASE/12 * (1+<global_monthly_population modifier of controller country>) * <state's current total population>.