In a sparesly populated area, using microwave, point-to-point radios? You very well may be the only subscriber on that first hop from your home network, and that first hop is likely in a geolocation database (this is certainly the case for my cousins farm).
In a densely populated area? Like a residential tower with 100 units? Your next hop off your home network might be on-prem equipment from your ISP that resides in the telecoms closet in your building, which is also in a geolocation database.
There is a broad spectrum of accuracy between these, and it's big business to effectively geolocate users, mostly for advertising, sometimes for compliance, and generally not to the benefit of users :P
Either of those can factor-into relative accuracy of geolocating your public IP