Hello Conal,
Kindly go through the responses provided below, for your various concerns over Cloud Endpoint:-
1. Geographical Location of Google Cloud Endpoint
As of now, the location of this service is available globally around the world. This service is not binded towards a specific location. You can check the details of various ‘GCP resources global availability’ by referring the help center article on Cloud Locations.
2. Why the request always routed to Mountain view location?
Most of the external Geo IP services are depending upon the SWIP database. And for this reason, most of the Google’s IPs are SWIP’ed to the Mountain View, CA. due to this, even for a GCP resource which is created outside (in your case South America Region) the US shows its IP location as in the US. However, your resource’s actual hardware facility will be located in the region you have selected. You can also go through this Google discussion thread which will give you more comments on a similar concern.
3. Plan to create an endpoint in South America.
As I said in my first answer, this resource is globally available. You can check the infrastructure map where it shows the ‘Edge Points of Presence (PoPs)’, which covers over 90 internet exchanges(includes South America region) and over 100 interconnection facilities around the world.