This article is written and contributed by Coalfire Federal, the leading provider of federal cybersecurity advisory and assessment services and Secureframe's trusted C3PAO partner.

Scoping your Controlled Unclassified Information (CUI) boundary is one of the most important steps toward passing your CMMC Level 2 assessment.

Done well, it can shrink your compliance footprint, reduce costs, and minimize risk. Done poorly, it can lead to missed requirements, confusion, or even a failed assessment.

Here’s what you need to know.

What is CUI scoping?

Scoping defines which parts of your organization will be included in the CMMC assessment—based on where CUI is processed, stored, or transmitted. This includes people, systems, and workflows that “touch” CUI.

If you don’t clearly define your boundary, you risk over-scoping (adding unnecessary systems and costs) or under-scoping (missing requirements and failing the assessment).

The 5 key asset categories

CMMC assessments consider five types of assets when defining your boundary:

• CUI Assets – Systems or tools that directly handle CUI like contracts, technical data, or source code.
• Security Protection Assets – Security tools like firewalls, antivirus, or logging systems that help protect your environment.
• Contractor Risk Managed Assets (CRMAs) – Assets that don’t directly handle CUI but might interact with it. You’re responsible for managing their risk.
• Specialized Assets – Operational tech, IoT devices, or test systems that may be indirectly involved.
• Out-of-Scope Assets – Systems that don’t handle CUI and are excluded from the assessment.

What impacts your scope?

Every organization is different. The size, structure, and complexity of your operations all play a role in how your scope is defined. A single-site business will have a very different scoping strategy than a global enterprise.

Cloud services and external providers also affect your scope. If you're using a cloud or managed service provider, make sure shared responsibility is clearly defined and documented.

Why scoping matters

Getting your CUI boundary right leads to real advantages:

• Smaller Scope, Lower Costs
  Limit the number of systems and users in scope to reduce assessment prep time and ongoing compliance overhead.
• Clear Compliance Map
  Your assessor needs a clear picture of how CUI flows through your environment and what protects it. Good scoping helps you tell that story.
• Less Risk of Failure
  Poorly defined boundaries create blind spots—and blind spots are where failures happen.
• Stronger Security Posture
  When you understand what’s in scope, it’s easier to apply consistent protections across the right assets.
• Faster Path to Certification
  The clearer your scope, the easier it is for your C3PAO to assess and validate.

Where to start

• Build a data flow diagram to visualize how CUI moves through your systems.
• Document the systems, users, and third parties involved.
• Cross-reference with CMMC practices to make sure everything in scope meets requirements.

Your CMMC assessor will expect this level of clarity—and your success depends on it.