In what geographical region is my S3 bucket stored?

You can use the GET Location Bucket request. Most probably your bucket is in US.

Unless you specified something else, it'll be North America.

If you log in to Amazon web services, and view your usage report, it'll tell you whether it's EU / US or something other.

From reading the Amazon S3 / MapReduce stuff, the regions are different between the two apps, so you probably want to stick to either EU or US (rather than east or west).

Cheers

For anyone else who comes across this looking for a way to determine the region of a bucket, regardless of whether you're the bucket owner (which is a constraint of GET bucket location), use HEAD Bucket, e.g.:

curl -sI foo.s3.amazonaws.com | awk '/^x-amz-bucket-region:/ { print $2 }'

which returns the value of the header x-amz-bucket-region for the bucket "foo", in this case:

us-east-1