AWS IAM inline policy for a user that gives them access to a specific region. Definitely not complete but good enough for me, for now for dev.

gistfile1.txt

{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Effect": "Allow",
            "Action": "*",
            "Resource": "*",
            "Condition": {
                "StringLike": {
                    "aws:SourceArn": "arn:aws:*:us-west-2:*"
                }
            }
        },
        {
            "Effect": "Allow",
            "Action": "s3:*",
            "Resource": [
                "arn:aws:s3:::*-us-west-2",
                "arn:aws:s3:::*-us-west-2/*"
            ]
        }
    ]
}