‘When you access Twitter, we may receive information about your location, such as your IP address, precise location information from GPS, or information about wireless networks or cell towers near your mobile device. We use information about your location to determine the country setting for your account, based on the countries where we make our services available. If we are unable to successfully resolve your location to one of these countries, it will be set to the United States by default.‘

https://help.twitter.com/en/managing-your-account/how-to-cha...