How to deal with Shapefiles missing Projection information in QGIS 🗺

Your best bet is to find the proper projection system by including the prj file in the same directory as the shapefile. If not available, try looking for the projection information (EPSG code) from where you got the file or the included XML meta data which can be opened in your web browser.

As a last resort, you can use QGIS Find Projection tool (use the Type to locate box in the lower left) after loading the shapefile to get potential projections. That won’t get you one answer but will narrow down the options. Be aware that using the wrong datum with the right coordinate system will introduce small errors in the projection – often a couple hundred meters or less, so if things are slightly off try a different datum. But try to find the official projection from the prj or xml file.

Store your own data as geopackages to avoid lost prj files and future projection issues.