How does Chrome know where I am?

Question

When giving permission to chrome to share my location with a webapp on my laptop, even with a VPN, chrome is able to tell my location accurately. How is chrome doing this? The docs say chrome sends a request to "Google Location Services". I understand that it must be related to my wifi network, but I'm not sure how it works past that... Thank you.

jschveibinz · Accepted Answer

Not sure, but it could be through MAC address and previous knowledge of your location:http://answers.google.com/answers/threadview/id/765054.html