Provenance refers to the details about the entities, activities, and individuals involved in the creation of a piece of data or an object, which can help assess its quality, reliability or trustworthiness. This paper describes an ontology that can be used to represent provenance and contextual information about Patient Generated Health Data (PGHD) shared with an Electronic Health Record (EHR). We created the ontology leveraging existing standard ontologies. Further, we chose and modeled important concepts based on literature that captures contextual information relevant to clinical decision making. We illustrated our ontology using a use case from literature and evaluated the ontology using competence questions. In the future, it will be useful to employ this ontology in translating the PGHD collected for clinical decision making.