Azure US Government Regions
The Azure portal for these regions is https://portal.azure.us.
Azure Australian Central Regions
The Azure portal for these regions is the same as other public regions, which is https://portal.azure.com. But the Australia Central region and Australia Central 2 region are dedicated to Australian and New Zealand government organizations and partners. Whitelisting is the method that Microsoft Azure uses to restrict access to these regions. For more information, see https://azure.microsoft.com/en-us/global-infrastructure/australia/. Contact your Microsoft Azure Account Team to submit an eligibility request to get whitelisted for these regions.