SCI Compartments
SCI compartments are subdivisions within Sensitive Compartmented Information that separate different types of intelligence based on their sources and methods. Each compartment has its own access requirements, and holding TS/SCI does not grant automatic access to all compartments.
Quick Facts
| Base requirement | Top Secret clearance + SCI eligibility |
| Access method | Must be "read in" to each compartment |
| Purpose | Protect specific sources and methods |
| Control | Intelligence community oversight |
How Compartments Work
The compartment system ensures that access to sensitive intelligence is limited to those with a specific need to know[1]. Key principles:
- Separation - Information in one compartment is isolated from other compartments
- Individual access - Each compartment requires separate approval
- Need to know - Access is granted only for specific job requirements
- Read-in process - Formal briefing and acknowledgment before access
Common Compartment Categories
While specific compartments and their meanings are themselves sensitive, several categories are publicly known[2]:
SI (Special Intelligence)
- Relates to communications intelligence (COMINT)
- One of the most commonly required compartments
TK (Talent Keyhole)
- Relates to satellite imagery and reconnaissance
- Often required for imagery analysis positions
HCS (HUMINT Control System)
- Protects human intelligence sources
- Required for certain intelligence operations roles
G / GAMMA
- Particularly sensitive SIGINT subcategory
- Very limited access
Subcompartments
Within major compartments, there may be additional subcompartments that further restrict access. For example, you might be read into SI generally but need additional access for specific SI subprograms.
Marking and Handling
Documents containing SCI are marked with the relevant compartment designations[2]. A document might be marked:
TOP SECRET//SI/TK//NOFORN
This indicates Top Secret classification, SI and TK compartment information, with no foreign national access.
Access Requirements
To access a specific compartment, you typically need:
- Top Secret clearance
- SCI eligibility determination
- Demonstrated need to know for that compartment
- Formal read-in briefing
- Signing of compartment-specific NDAs
Related
References
- ^ ICD 704: Personnel Security Standards and Procedures Governing Eligibility for Access to SCI. Office of the Director of National Intelligence. Accessed 2026-01-08.
- ^ Intelligence Community Classification and Control Markings. Office of the Director of National Intelligence. Accessed 2026-01-08.
- ^ Executive Order 13526: Classified National Security Information. National Archives. Accessed 2026-01-08.