Awesome work. Just out of curiosity, where do you source the maps from? In france IGN has a ton of old maps

Around 90% of the maps currently on the site are from the US government (USGS). The last 10% are from public institutions and libraries and this is the newest segment that I'm actively working on growing. My hope is to flip this ratio with time.

I also have a few partnerships in the work with some private collections but those have proven trickier to actually get to a "yes". It also involves a lot of bespoke work to process and ingest each individual source so I'm not focusing as hard on this type of sourcing anymore.