Given federal mandates recommending document standards, increasing numbers of electronic clinical documents being created, and local initiatives/projects using clinical documents, there is a growing need to better represent clinical document metadata. The HL7/LOINC Document Ontology (DO) was developed to provide a standard representation of clinical document attributes with a multi-axis structure. Prior studies have demonstrated the need for extension of DO axes values and proposed new values for some axes, but significant gaps remain for representing the DO “Setting” axis. This study aimed to extend the “Setting” axis by combining the current values in the DO with values from 5 other sources. Evaluation and refinement by subject matter experts over a series of four iterative sessions resulted in a reorganized hierarchy with 254 additional values from a baseline of 20. Incorporating a comprehensive set of “Settings” in DO provides better representation of clinical information across the healthcare ecosystem.