This page is for a description of the various upgrades that can be undertaken in individual provinces within the game Hearts of Iron 3.

All province upgrades must be build in the production menu using Industrial Capacity (IC), but they can be started in each province.

All upgrades may be damaged, for example with strategic bombers. Damaged upgrades do not impart any bonuses until they are repaired, which is done automatically and for free.

Some upgrades may be built from the production menu and not assigned to a province until they have been completed. In this way, one may quickly built up anti air in a province or place these upgrades only as needed. Air bases produced in this manner may only be placed as a first upgrade in a province and cannot go above level one except by upgrading the air base specific to that province. Land forts and coastal forts may not be constructed at all in this way.

Air BaseEdit

Air Bases allow for planes to land there. A higher Air Base score improves repair/organization regain rates as well as allows more supply to be used by the base, which means more planes can be used in that province.

Naval BaseEdit

Allow for the docking of ships. A higher Naval Base score improves repair/organization regain rates. Also allows more resources/supplies/fuel to be shipped through that province.

Industrial CapacityEdit

Each level gives an unmodified IC of 1. This IC is used to build things in the production menu.

Coastal FortEdit

A coastal fort gives a combat bonus to a land unit stationed in that province when a enemy unit try an invasion from the sea to that province.

Land FortEdit

Each level of land fort increases the defensive bonus of that tile by a small amount. A tile that has a full 10, undamaged, forts gives a -90% modifier on any army that is attacking this tile. This is a very significant debuff, but it takes years to take a tile from 0 forts to 10 forts and is very expensive in IC. Defending at a river is often a better choice than taking the time to build Land Forts, meaning building Land forts across rivers will be the best choice.

Anti-Aircraft GunsEdit

AA Guns are very quick to be built but are not very effective in small numbers. When level bombers bomb a province, a few AA Guns are usually not enough to fight them off and the AA Guns will soon be damaged and rendered useless until they repair. Because of how fast and cheap they are to build, however, one can take a province from 0 to 10 AA guns in about a year and a half. They can also nicely complement fighter support as well as AA units (not to be confused with provincial AA Guns).


Infrastructure is used to transport supplies and units around the map. Most provinces start the game with a high infrastructure score. The provinces that start with lower infrustructure are places like those in Africa or certain parts of the Soviet Union. Many poorer or more rural areas of europe will start with less than complete infrastructure but still usually have at least 8/10 infrastructure. Infrastructure may only be built once the appropriate technology is researched. This technology is unavailable until industry is researched enough. The big factions start with these technologies already researched.

Radar StationEdit

Radar stations give small bonuses to allied air units in surrounding tiles. They also give other bonuses, such as a slightly enhanced vision

Nuclear ReactorEdit

Nuclear reactors help in the construction of nuclear bombs. The nuclear bombs lower national unity so drop it on VP cities, preferebly capital cities. A thing to remember is that a nation doesn't surrender only from nuclear bombings.

Rocket Test SiteEdit

Rocket test sites increase Rocket practical knowledge which helps when researching later rocket techs.