LocateJS is a site that attempts to determine your location “by analyzing your connection and system data.” If you are attempting to mask your location–as I typically am–this provides a good reality check to just how much data your system and connection expose about your true location.
In my case, the tool correctly predicts that I’m in the United States (which I generally do not try to hide) but was off by almost 1,000 miles from the city I’m located in.
The Github repository for the site includes some helpful suggestions on how to obfuscate your physical location.