.HOI4 File Extension
File TypeHearts of Iron IV Game Save File
What is a HOI4 file?
An HOI4 file is a game save file created by Hearts of Iron IV, a World War II strategy video game. It contains saved campaign progress, which includes the placement and amount of military resources, battle history, and the time and date.
In Windows, HOI4 files are typically saved in the following location:
C:\Users\[Username]\Documents\Paradox Interactive\Hearts of Iron IV\save games