Sift uses third-party lists to determine IP location. These are regularly updated, as we strive to provide the most accurate information regarding a user's IP location. There are a number of different publicly-available lists that can be used to search for IP location. These lists vary, and it should be clear that none of these lists are 100% definitive or accurate. The occasional instance of what appears to be a mismatch between what Sift states is an IP's location and what another resource says is this IP's location is not cause for alarm. If you believe you are seeing more than the occasional mismatch in what Sift reports as an IP's location, please contact Support by clicking here. In your support ticket, please remember to include examples of users for which Sift has provided an IP location, as well as a corresponding different IP location, i.e. a URL to a site that provides an IP location different from the one Sift provided.