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HOI4 (Hearts of Iron IV): USA Guide – How to Win Every Time

HOI4 (Hearts of Iron IV) USA Guide - How to Win Every Time

Hearts of Iron IV (HOI4) is a captivating grand strategy game developed by Paradox Interactive, immersing players in the role of a nation’s leader and offering the possibility of reshaping both their nation’s destiny and the course of world history. Among the various players on the global stage, few can rival the enormous potential of the United States of America. With its vast resources and untapped power, the USA has the capacity to become the decisive force in both the European and Pacific theaters of war in HOI4. In this comprehensive guide, we will delve into the most effective strategies for harnessing the American juggernaut, optimizing its strengths, and achieving victory on a global scale. Here is how you can easily win the war in HOI4 as the USA.

USA Starting Position in HOI4 

As the sleeping giant, the United States of America is easily the best nation for a player to play with in HOI4. With vast resources untapped and a burgeoning industry waiting to take off, America has only to shed the effects of the Great Depression in order to take command of its own destiny, whichever path it may take.

The USA starts off with 24 free civilian factories, 10 military factories, and 22 naval dockyards in HOI4. With the low number of military factories and the effects of the Great Depression still active here, it’s expected that building a proper army, navy, and air force will take considerable time, which means staying out of the early parts of the Nazi invasion of Poland.

The first priority for any player will be to clear the Great Depression debuff and get rid of the Undisturbed Isolation economy law. Getting rid of those two things will easily boost America’s capabilities in preparing and then waging a war.

Technology-wise, the USA is on a good path for modernization in HOI4 and does not really need to catch up to speed with the European powers. Still, a great focus here is to get upgraded naval vessels quickly so that we can relegate the outdated models to convoy escort duties, much like the United States did historically.

The USA Military is pretty lackluster when it comes to the army in HOI4, as it only contains 36 divisions, with a great number of them requiring immediate reinforcements and supplies in order to reach full strength once more.

The navy, however, is one of the world’s finest, as demonstrated by the 200+ ships capable of conducting operations on two oceans (the Pacific and the Atlantic). Though this can be improved even further by developing advanced technology.

Opening Economic Moves

As mentioned, USA contains a vast amount of untapped resources in HOI4 waiting to be used by the player. With this in mind, it is wise to build a combination of civilian factories and infrastructure in areas with resources available in order to fully maximize our economy and bring some stability.

The USA possess more than 100 civilian factories at the start of HOI4 but fails to have all of them accessible due to the effects of the Great Depression. Still, once that is out of the way and America can access the normal economic laws, this great number of factories can help immensely.

Since the United States has nearly all of the key resources available, we only need to import rubber and chromium in order to build our carriers, battleships, and planes. This is quite important since our need for modernization takes priority over building an army in the early game.

Opening Military Moves

For the army, arrange all forces into two armies and set them against Canada or Mexico. We’re not going to invade Canada or Mexico, but this is easier to manage and keep track of than having all of them on multiple Pacific islands. Later on, we’ll arrange the troops in preparation for a war with Japan.

For the navy, there are two possible paths to go through: either build at least 4 fleets of modernized vessels (ideally 2 aircraft carriers, 3 battleships, 4 heavy cruisers, 4 light cruisers, and 15 destroyers) or pair your strongest and most modernized vessels into a single strike force while having your outdated ships serve as your patrol vessels.

If the former is taken, you will ideally need four such fleets of each carrier group to cover Hawaii to the Japanese mainland itself. Feel free to further supplement your carrier groups to outnumber the Japanese, though having more than three aircraft carriers will result in penalties.

If the latter is taken, station your fleet on Guam. Since no enemy naval invasions are expected anytime soon, we can focus on bringing the Japanese navy into a single decisive battle. Set your main battle fleet on strike force duty while creating as many patrol fleets as possible in the zones around Japan.

For the air force, our main goal here is to ensure that all aircraft types are ideally constructed with a greater focus on fighters, CAS, naval bombers, and their carrier equivalents. In the future, we should keep an eye on modernizing planes while also producing new types such as the strategic bomber (which will allow us to use nukes).

For all branches, it would be best to set them to train from the start since we don’t expect to be joining the war soon.

Opening Political Moves

Since the Great Depression is our main focus moving forward, we will not be able to appoint any advisors so far, though once we clear this route, we will need to appoint Robert Taft as our first political appointee. Taking either Henry Morgenthau or Harry White will be useful as well, since the US has a large civilian industry dedicated to consumer goods. The last choice is up to the player’s choice, but Henry Stimson is not a bad target.

For the Chief of Army, it is better to get Dwight Eisenhower since his bonus attack will be useful for us. For the Navy, William Halsey Jr. is our preferred pick since we need to maximize the damage from our carriers.

Now, for the Air Force, George Kenney is a solid choice since he increases the reliability of our planes. For Military High Command, take Mark Clark, Frank Fletcher, and Thomas Kinkaid.

The logic behind these choices is that Clark will better our infantry divisions (he can be swapped in the future for any general you promote for motorized, mechanized, or armor units), Fletcher will continue to boost our carrier capabilities, and Kinkaid will make our invasion speed proceed faster, allowing us to catch the enemy off balance.

The Democratic Path (Democratic Party) for USA in HOI4

This path will try to emulate and improve on the historical path the United States took prior to joining the Second World War. By taking these steps, it is hoped that the USA will be more prepared for war in HOI4 than it was historically and properly help the Allies.

Moving Past the Great Depression

To start, we need to get rid of the Great Depression national focus as soon as possible. Take the Continue the New Deal focus since Roosevelt will continue to be our President for the foreseeable future. Take the WPA, Agricultural Adjustment Act, and then Suspend the Persecution focuses. Be sure to keep lobbying and keeping most of the Senate and House on your side before taking on some of these focuses.

Next, we’ll be adding a sprinkle of Communist flavor to our democratic path. Take the Union Representation Act, Accumulated Wealth Tax, Scientific Research and Development Office, and Fair Labor Standards Act. If you need Earl Browder in your government, pause the game, appoint him, take the focus, unpause the game for a day, and then remove him immediately, as we intend to remain democratic.

Be sure to take anti-communist measures in the decision tree to remove any Communist influence. At the same time, appoint Robert Taft as soon as possible while also performing more

Once we deal with the economic mess, we can move forward with the Neutrality Act, Arsenal of Democracy, and Scientist Haven. We need to take these three so that we can start boosting the industrial power of America while also putting the debuffs on the lend-lease treaty (which we won’t be touching).

Building the Economy Back Up

It’s time to make the USA the economic giant we know it can be in HOI4. Since we need a lot of resources to start, we need to start by building the maximum infrastructure in the following states first:

  • New England
  • New York
  • Pennsylvania
  • Ohio
  • Indiana
  • Michigan
  • Illinois
  • Missouri
  • Virginia
  • Maryland
  • New Jersey
  • Texas
  • California

Those states will be our major industrial hubs (since they have a mix of huge building slots and resources). Following this, we need to construct the maximum number of civilian factories in the same territories, as their maximum infrastructure will boost our civilian factory construction speed.

Once done, focus on maxing out the infrastructure in the following states:

  • Tennessee
  • Wisconsin
  • Minnesota
  • Utah
  • Nevada
  • Idaho
  • Louisiana
  • Georgia
  • Alabama
  • North Carolina
  • South Carolina
  • Florida

With this done, our focus moves onto having enough naval dockyards to rapidly modernize and outfit our navy for war. Try to get around 80+ naval dockyards built (remember that the Two Ocean Act Focus will give 10 free dockyards). Once done here, build about 20–30 synthetic refineries in your inland states with maximum infrastructure so that our rubber and oil demand will be easily met.

Now we are preparing for a naval invasion. Build a max-level port, airfield, and radar in Guam so that we can launch our attacks on the Japanese navy and launch an easy invasion into the heartland of the Japanese Empire. Feel free to construct ports and airfields in the Philippines as well to ease the supply demands on Guam.

Once all preparations are complete, start converting civilian factories to military factories until 50–60 civ factories are left (do not start this process if you haven’t completed the Wartime Industry focus). After this, feel free to continue building as you prefer since our main preparations are complete.

Growing Our Advantages

For our research tree, we need to focus on industrial (including synthetic production), electronics, naval vessels and supports, aircraft, and infantry, in that order. With the addition of a new research slot, we can perform more research at once.

With our navy, we need to have at least the 1936 or 1940 models for our ships. In terms of aircraft carriers, the Yorktown-class is already good enough for our needs; we just need to build at least 8 of them with 30 fighters and 30 naval bombers each.

If you are capable, send a volunteers attaché to Nationalist China to earn more XP and give the Chinese a small boost against the Japanese. If they protest, keep the attaché there and ignore the Japanese.

Start filling out the military staff with the best advisors mentioned earlier. For design companies, take Gruman for aircraft designer, Electric Boat Company for naval designer, General Motors (only possible) for industrial concern, Rock Island Arsenal for material designer, and Chrysler for tank designer.

Feel free to reduce the trade law to an exports focus if you require more resources for your industry. The reduction in buffs won’t hurt us as much as other nations. You shouldn’t take Free Trade until at least 1940.

Once you’ve taken the Guarantee the American Dream focus, you should have enough focus to go through the The Giant Wakes and Wartime Industry focuses. After that, we can finally move our focus tree to the military side with the War Department, Two Oceans Navy Act, Maritime Commission, Bureau of Ships, and Escort Effort focuses in that particular order.

The Ever Closer War

After the Navy focus tree of the War Department, we can move to the Army this time. Take the following USA HOI4 national focuses in the particular order:

  • Military Construction and USACE Projects
  • Selective Training Act
  • Louisiana Maneuvers
  • Militia Organization Act
  • Army of the United States
  • Women’s Armed Service Integration Act

For the Air Force, take the Air War Plans Division and Air Support focuses since our air force (excluding the ones serving on carriers) will be predominantly composed of fighters and close air support planes.

With these focuses, we can start retraining our units. Since the manpower pool in America is expected to be large, a 25 or 40 width unit is possible, as it will give us a greater advantage when breaching the Japanese beaches.

With the landing craft technology, we should be able to station 12+ divisions on Guam, though be sure to keep an eye on the logistics of the island since any shortages in supplies will also affect our invasion fleet. Set a naval invasion order for your troops, and once this is complete, feel free to replace Thomas Kinkaid with Joseph Stilwell if the latter is still available.

Start stationing naval bombers and fighters on Guam as well, since we need them to sink any enemy convoys that attempt to land on Guam and the surrounding islands. Do the same for the Philippines, but more fighters need to be stationed here as Japanese Air Power in the region should be stronger due to Taiwan.

War with Japan

Once the war with Japan starts, immediately send our naval forces to their pre-assigned areas. With either strategy implemented, our goal is to use our carrier fleet to launch aerial attacks on their outdated fleet. Try to get the concealment expert trait on your main admirals since it helps hide our carriers from the Japanese vessels.

Be sure to set the naval fleets to auto-reinforce as well, since capital ships without any escorts are easy prey for the Japanese submarines.

Given our preparations so far, it should be fairly easy to get rid of the Japanese navy, especially if we’ve already unlocked most, if not all, of our naval doctrines. Once their fleet has been neutralized to the point of no longer being a major threat, change your strike force duty to invasion support and launch the assault from Guam.

Since most of the Japanese victory points come from their home islands, taking all their cities and provinces in Asia with our forces should force them to capitulate. If not, take the remaining provinces (usually Korea and/or Taiwan). Remember to secure a supply route for your land forces on the mainland before launching an offensive.

Once Japan surrenders, we can look forward to taking on Germany and any other threats.

Global Hegemon

After the Pacific War, the USA should be in a dominant position to either influence the war in Europe (if it’s still raging) or exert its influence as the world’s predominant superpower in HOI4. With a large navy and an equally powerful army at its disposal, the United States can choose whichever country it wishes to attack and conquer at will.

For bonus points, don’t forget to build atomic bombs and use them at will since the United States can easily replace them once all states have a nuclear reactor in them.

The Communist Path for USA in HOI4

This HOI4 path will seek to turn the USA into a Communist country capable of taking over the leadership mantle of the Comintern or creating its own Communist bloc to rival the USSR. On this path, we’ll be dealing with the Second American Civil War branch as well.

Preparing for the Civil War

To start off, the rebels (the Confederacy) will start off with the same technology that the player has once the war starts. For that reason, focus your research on electronics and industry so that they will not gain parity in terms of military research. Likewise, do not construct anything in the following states, as they will try to secede:

  • North and South Carolina
  • Mississippi
  • Florida
  • Alabama
  • Georgia
  • Louisiana
  • Texas
  • Virginia
  • Arkansas
  • Tennessee

Train at least 10 cavalry divisions, with five each stationed near Texas and Virginia. The former will give us access to the oil reserves, and the latter is usually the capital of the Confederacy. Leave at least 36 divisions to build up the remainder of the front (ideally 24 from Maryland to Tennessee and 12 divisions to Texas).

Immediately go down the communist tree by taking the Agricultural Adjustment Act, Suspend the Persecution, and Reach Out to the Wares Group focuses and appointing Taft to the government for that extra bonus PP. After this, hire Browder as soon as possible and ignore any protests by continuing your lobbying efforts.

Rush taking the Guarantee the American Dream and Worker Management Act. The former will prevent the midwest from going neutral and detaching from the government, and the latter will finally get rid of what remains of the Great Depression debuff.

Civil War Starts

Before the war starts, at least have enough political power in hand (150 PP) to change the economy. Likewise, it’s wise to have your military staff already appointed, if possible, so that all military advantages can be gained.

With our troops on their borders, start rushing the Confederacy’s capitals when it all begins. Every state you capture will give you two extra divisions, so feel free to have them join the fighting or disband them for the equipment. Either way, the war should be good as won with the Confederates too stunned to prepare for the blitz tactics.

Re-integrate states as soon as possible, and once possible, change the government type to a Communist one. The United States is finally red and the Communist ideology has won.


Post-War, the United States has two choices to make: either it joins the Soviet Union and eventually annexes it to join the Unions, secures China for the Chinese Communists, or builds its own faction via the Hemisphere Defense focus.

If the United States joins the Soviet Union, you can actually end the war with the Axis powers. By joining the two countries together, the Axis forces will be forced back to the borders, provided they are not at war with the United States.

If secure China were taken, the Philippines would have to be retaken and then used as a base of operations for attacks against the Chinese on the mainland, while Guam would remain our base of operations against the Japanese homeland.

If the third option is taken, then the world is your oyster as you will be the only major power in your faction.

And that is all you need to know about how to win as the USA in HOI4. Check out other interesting HOI4 guides and articles:

Based in Santa Rosa, Philippines, Jonathan Ledesma is a Freelance Writer for Raider King.
Jonathan Ledesma
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