AWS SDK for .NET Documentation
Region Property
AmazonAmazon.Route53.ModelResourceRecordSetRegion Did this page help you?   Yes   No    Tell us about it...
Regional resource record sets only: Among resource record sets that have the same combination of DNS name and type, a value that specifies the AWS region for the current resource record set.

Constraints:

Length
1 - 64
Allowed Values
us-east-1, us-west-1, us-west-2, eu-west-1, ap-southeast-1, ap-southeast-2, ap-northeast-1, sa-east-1, cn-north-1

Declaration Syntax
C#
public string Region { get; set; }

Assembly: AWSSDK (Module: AWSSDK) Version: 1.5.60.0 (1.5.60.0)