Hi @MattBuck ,
It's not available on AWS GovCloud.
1) The first link you attached is the authoritative source for feature availability by region. If you can't find it there it means the feature is not available in specific region
2) And I think this limitation makes sense from architectural reason - while not explicitly stated in docs: Vector Search depends on serverless / AI platform capabilities (endpoints, scaling infra, etc.) GovCloud has reduced / limited availability for many serverless + AI features (visible in the same region matrix) So this isn’t just a documentation gap - it aligns with broader platform constraints in GovCloud.
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