Geolocation works by capturing the IP address from the open made on the email. The IP is looked up by our system and the location is recorded, and then the IP address is discarded.
Many ISPs may not provide the exact town/city locations with the IP addresses. Laptops may also cache the IP from your previous location and may not have updated. Mobile opens made on a mobile data network (not using wifi) can be tracked differently. For apps running on a mobile device, the apps can use GPS and cell tower triangulation to determine the location. For an image loading in an email client, the IP is the same IP everyone else on that network in that area is using. AT&T in Boston, for example, is routed via New York and that is where the IP's location shows up.
Geolocation is also affected by Google and Yahoo! image caching. Since the open tracker pixels used to relay information about Gmail opens are now cached on Google or Yahoo! servers, you would see the location of Gmail or Yahoo! proxy servers. We exclude opens on clients which use image caching from geolocation reports, to avoid reducing the accuracy of the report.
You can also find a map of your geolocation report within each tracking code. The Opens by Country map will show areas with high amounts of opens as darker blue, and lower amounts in lighter blue. You can move your mouse along the map to show the exact amount of opens for each country/region.
The geolocation feature will break down your opens by country, and then by region. It will also show you the opens in each country and region broken down by Desktop, Mobile, and Webmail.