Azure Arc Private link scope regions

There are two different regional relationships to keep separate.

For Azure Arc-enabled Servers, Microsoft requires the Arc-enabled server resource and its Azure Arc Private Link Scope to be in the same Azure region.

However, the Private Endpoint and its VNet must be in the same region as each other, but that region can differ from the Arc server/APLS region.

So, for example:

Arc Server resource: North Europe

Arc Private Link Scope: North Europe

Private Endpoint: West Europe

VNet: West Europe

is regionally valid according to those rules.

Azure Monitor is separate. The Arc Private Link Scope doesn't automatically make Azure Monitor Agent traffic private. Microsoft explicitly states that services such as Azure Monitor require their own Private Link/private endpoints.

For architecture, I would align Arc resources/APLS by region and design your Private Endpoints around the VNet/ExpressRoute ingress points.

For the exact cross-region cost, I wouldn't assume zero or a fixed charge—the answer depends on the actual ExpressRoute/VNet/Private Link traffic path and current regional bandwidth pricing. Model that specific flow with Azure pricing rather than using the Arc resource's logical region alone.