World War II by Day is a compendium of data about the largest conflict in world history, as well as a source for visualizing the data. In many years of private interest in the War, I’ve wanted to find data about the war, but there are few organized resources with graphical interfaces. This makes it difficutlt to find data such as where the 79th Infantry Division was located on September 16, 1944? Who was its commanding general? What larger formation was it assigned to? What components were attached to it?

My hope in building this interface is to organize this type of information consistently and with context. After looking up information on the 79th Infantry Division, you can learn about the structure of US Infantry Divisions, as well as its sister units in XV Corps.

This project is of potentially enormous scope. The goal is to create a system that can incorporate any type of data about World War II into intuitive visual representations. There were approximately 2,000 frontline combat divisions in the war. Finding and organizing the data for the 61 American divisions who fought in northwestern Europe for one year is already a daunting task. I can't imagine what’s involved in learning about the 1,000 Soviet divisions who fought for four years. Millions of Nationalist Chinese fought in the war, but data on their units and commanders has proven elusive.

This is where I hope for others will help. If you’ve reached this site, you probably have a greater than passing interest in the War. You may know where some of this information can be found. You may be willing to gather and submit data to be incorporated. You might live in Ottawa, or Brussels, or Belgrade, or Athens, and have access to local records. You might be able to translate records written in one of many languages I do not understand. If you are interested in the project, I encourage you to contact me, letting me know how you would like to help.


Unit Types:
Mountain Infantry

Frequently Asked Questions:

  • What data do you have right now?
  • Most of the basic data on the Western Front after D-Day is complete for echelons at and above division level. I would like to add more subordinate officer roles to non-American units. I am also interested in finding more data at the regimental (and, perhaps, battalion) level.

  • Is the data accurate?
  • This data is fairly accurate, but it’s not perfect. Locational data is, at best, accurate at the town or village level. Divisions consisted of around 15,000 personnel; they were not all in the exact same location. When I can, I use headquarters locations. The maps are run via Google Maps, which is the only feasible way I know of. But these are current maps, and a lot has changed in 80 years. Road networks are different, but even features like the paths of rivers and coastlines have changed meaningfully. Place names are often different; especially in France towns and villages have different names than they did in 1945. There is also the possibility of manual errors. If you find something wrong on a map, let me know, preferrably along with your source.

  • What does the map mean?
  • There is a key at the bottom of each map, but generally:

    • The marking above the unit box represents the size (“XX” for division, “XXXXX” for army group).
    • The marking in the box represents the type of unit (e.g. little wings mean airborne infantry).
    • The color of the box represents the nationality (e.g. blue for the United States, green for France).

  • What data are you looking for now?
  • My near term goal is to complete the picture of northwest Europe from D-Day through May 1945. I plan to work on fixing unit assignments, as well as add information about subordinate formations.

  • Why do you only have maps and data, no personal stories?
  • There are many other sources that help you learn it was like to be in the war, from biographies of 5-star generals to interviews with average GIs and diaries of civilians caught in the crossfire. I might create a reading list of my favorites at some point. Eventually, it would be great to link my data about units and people with others stories of what the war was like for people who experienced life at that place andd time.

  • What comes next?
  • One day, I'd love to have all fronts, all nations, and all years – even air and naval units. So I'm gathering any data I can find; I’ll store it until I’m ready to incorporate.

  • Where is the data from?
  • All over; see the Sources page. When possible, I use unit-level data produced by the relevant governments (often via a intermediary location). I do not use data that I have reason to believe is copywritten, but it is possible I’ve erred.

  • What if I want your data?
  • Please reach out to me with specifics. Until and unless I find a reason not to, I am happy to provide raw data.

  • Are you a bit nuts?
  • Probably.

  • What’s in it for you?
  • It's just for fun, and a way to work on web development skills. My main providers are Heroku and Google Maps; both have free tiers, but you'd be amazed how the rows of data and API queries add up. At some point I might try to break even. We’ll cross that bridge when we come to it.

    Until then - enjoy the maps!

Total Units: 362
Total Locations: 6922
Total Commanders: 1863