The objective of the Department of Homeland Security (DHS) Core Ontology for Maritime Domain Awareness effort is to provide DHS with the base of a semantic framework, in the form of a DHS Core Ontology, a Maritime Domain Awareness Ontology, and a Computational Analytic Ontology. The semantic framework will be an evolving part of the DHS data architecture enabling the functionality to create data that is integrated, familiar and trusted. The base framework will enable evolution by having a core ontology of DHS terms which are then reused to create interoperable ontologies covering the numerous and diverse domains of interest to DHS.