[Spittie]

The easiest way would be to use GeoDNS. You just have your DNS server send out a different IP according to the IP of the request.

See http://www.caraytech.com/geodns/ and https://en.wikipedia.org/wiki/Geodns

I've found this nice answer on StackOverlow that show the differences between Anycast, GeoDNS and using an http redirect: http://stackoverflow.com/a/25678199

[chubot]

Great thanks! It looks like the questioner ended up using AWS Route 53, which supports this kind of thing. I'm not using AWS, and there are other options, but that is the kind of thing I am happy to offload to AWS.