Azure Government vs AWS GovCloud for CUI Workloads

Most write ups of Azure Government vs AWS GovCloud try to declare a winner on authorization level. There isn’t one. At the level that matters for controlled unclassified information the two are equivalent, and any article claiming otherwise is selling something. The decision turns on three other things entirely: what your controlled data actually is, what each vendor will put in writing about DFARS obligations, and whether you are buying infrastructure or a place for people to work.

Before anything else, one correction that saves real money. Azure Government is not Microsoft 365 GCC High. They are separate products, separately purchased and separately administered. This article sits under How to Compare CMMC Compliance Options: Enclave, Full Environment, or Managed Service.

Azure Government vs AWS GovCloud: where they are the same

Read that table as a conclusion rather than a comparison. If someone is trying to sell you one of these on the basis that the other cannot hold controlled information, they are wrong and you should discount everything else they said.

One terminology note so you are not caught out. FedRAMP is renaming its baselines during 2026, and you will see High described as a certification class rather than an impact baseline. The substance is unchanged, but the labels on marketplace listings and vendor pages are inconsistent right now.

Where Azure Government vs AWS GovCloud genuinely differs

What each vendor will put in writing about DFARS

This is the most useful practical difference and almost nobody covers it.

DFARS 252.204-7012 requires that a cloud provider holding controlled defense information meets FedRAMP Moderate equivalency and complies with paragraphs (c) through (g): incident reporting, malicious software submission, preserving images and monitoring data for at least 90 days, forensic access, and damage assessment.

Microsoft publishes a third party attestation of DFARS compliance for Azure and Azure Government, along with a customer responsibility matrix, both downloadable from its trust portal. You can hand those to an assessor.

Amazon’s published DFARS material recites the requirement and directs you to contact them. Be careful how you read that. It is a documentation gap rather than a refusal, and the terms may well exist in government contract vehicles. But if you are buying today, one vendor lets you download the evidence this afternoon and the other requires a conversation. For a small contractor with no procurement leverage, that difference is worth more than any feature comparison.

What you are actually trying to protect

This decides it more often than anything else.

• If your controlled information lives in email, documents, drawings and chat, which describes nearly every small manufacturer, neither of these products solves your problem. You need a productivity environment, and the answer is GCC High or an enclave built on it. Azure Government gives you virtual machines, not Outlook. See GCC High vs GCC vs Commercial Microsoft 365 for CUI.
• If your controlled information lives in something you build, a hosted application, a data pipeline, a simulation environment, a product you sell to the government, then this comparison is the right one and either platform will carry it.

How hard it is to buy

AWS GovCloud sign up is a review of whether you are a United States entity whose account credentials will be managed by a United States person. It is close to self service.

The Microsoft government estate is heavier. Eligibility is validated before you are admitted and revalidated at renewal, and the productivity side cannot be bought directly at all, only through a licensing solution provider or an authorised government reseller. For a company under fifty seats, that procurement friction is a genuine project cost.

The impact level trap

A specific and expensive one. Deploying virtual machines at Impact Level 5 in the Azure Government commercial regions requires dedicated host isolation, which is a large fixed cost that does not amortise across fifteen users.

Before anyone designs to Level 5, check whether you need it. Level 4 is defined for controlled unclassified information. Level 5 is for controlled unclassified information requiring additional protection, including certain national security systems. Ordinary CUI at a machine shop is a Level 4 conversation. A surprising amount of small contractor spend has been aimed at a bar the contractor never had to clear.

The ITAR detail that catches people

If you handle export controlled data, both platforms support your obligations and neither certifies them. But note a real failure mode that Amazon documents openly: metadata fields outside the ITAR boundary, storage bucket names being the classic example, are not permitted to contain export controlled information.

The categories that trigger these restrictions are covered in What is Controlled Unclassified Information (CUI)?. Nobody thinks of a bucket name as a place where a violation can occur. Whichever platform you use, write naming conventions into your standards before engineers start building, because the cleanup is far worse than the prevention.

What neither platform gives you

A FedRAMP High authorization covers the platform. It does not cover what you build on it. Your identity configuration, your encryption choices, your logging retention, your patching, your access reviews and your incident response process are yours, inherited from nothing.

Amazon states this plainly in the shared responsibility framing, and Microsoft states that you are responsible for designing applications to meet the requirements and that it does not inspect or monitor what you deploy. A contractor who buys a government cloud and assumes the compliance came with it has bought a very expensive virtual machine. What operating one actually involves is in build vs buy: what an in house enclave actually costs.