Final answer:
The unit responsible for establishing check-in procedures and completing ICS Form 211 is the Incident Command Post (ICP) within the ICS organization.
Step-by-step explanation:
The unit within the ICS (Incident Command System) organization responsible for establishing check-in procedures and completing ICS Form 211 is the Incident Command Post (ICP).
The ICP is the physical location where the primary functions of incident command are performed, and it serves as the command center for managing and coordinating response efforts.
The ICS Form 211 is used for documenting personnel resources' arrival at an incident scene, including their name, organization, position, date, time, and assignment given.