Looking up the geolocation of an IP address is something that’s simple to do because there are so many sites out there providing the service for free. One downside is that many services cap you at how many requests you can make each day to try and avoid having people abuse their systems. You may think that you’ll never make more than a handful of requests in a day, but I’ve run into situations where that limitation was a problem. One example is when trying to figure out if a set of IPs performing a DOS attack on a site is in the same geographic area. In that situation you may be checking dozens of IPs all within a few minutes.
In those kinds of situations you can use a service like utrace or ip:2:loc. Both of the services have a similar interface where you can enter in an IP address and the resulting region will be displayed on a Google map. Nothing extravagant, but they’re extremely straightforward and I have yet to see any sort of limit on them.
If you’ve got your own services you use for looking up the geolocation of an IP address please share them in the comments below.