API Gateway sigv4ServiceName and sigv4SigningRegion properties not supported in us-west-2 region

The error you're encountering with "Unknown Property 'sigv4ServiceName'" and "Unknown Property 'sigv4SigningRegion'" in us-west-2 is not related to a regional limitation. These properties should be supported across all standard AWS regions including us-west-2.

When using SigV4 (Signature Version 4) for API Gateway integrations, the properties should work consistently across regions. If you're using SigV4a (an extension of SigV4), note that the region is not included in the credential scope, which might be relevant to your issue.

The problem is more likely related to your CloudFormation/CDK template or OpenAPI specification rather than a regional restriction. Here are some things to check:

1. Ensure you're using the correct API Gateway version and integration type in all regions
2. Verify that your CloudFormation template is properly transforming the OpenAPI specification
3. Check if there are any syntax errors in your template specific to the us-west-2 deployment
4. Make sure you're using the same AWS SDK/CLI version across all regions

If you're using Fn::Transform with AWS::Include to incorporate your OpenAPI specification, ensure the S3 bucket containing your spec file is accessible from the us-west-2 region and that the transformation is working correctly.
Sources
Troubleshoot Signature Version 4 signing for AWS API requests - AWS Identity and Access Management
Creating api gateway api from openapi specification with lambda integration does not create triggers | AWS re:Post