Hi, there are two general methods websites can use to detect your location:

(1) IP address

All web requests include your return IP address, which typically is assigned by your current network service provider (home, office, coffee shop, or VPN). There are many sites to look up the public data associated with your IP address. For example, https://www.iplocation.net/

(2) Precise location

If the site prompts Firefox to share your precise location and you approve it, Firefox will ask Windows for data on nearby wireless hotspots, and then send that to Google to look up the estimated lat/lon based on that data. More info: Does Firefox share my location with websites?

Site-Specific Features

If those methods do not work for Bing, there is a field on the Bing settings page where you can give it your address directly: https://www.bing.com/account/general#location

You can try to to clear the cookies to see if that has effect.

Clear the Cache and remove the Cookies for websites that cause problems via the "3-bar" Firefox menu button (Settings).

"Remove the Cookies" for websites that cause problems:

• Settings -> Privacy & Security
  Cookies and Site Data: "Manage Data"

"Clear the Cache":

• Settings -> Privacy & Security
  Cookies and Site Data -> Clear Data -> [X] Cached Web Content -> Clear

See also:

• https://addons.mozilla.org/en-US/firefox/addon/change-geolocation-locguard/