Enterprise Information Architecture (EIA) is a critical success factor for Business Process Re-engineering (BPR) and Information management. The knowledge of business information provides a vital leverage to the design of enterprise information architecture. This paper proposes an approach for semantically deriving EIA of an enterprise from the ontological representation of a given Business Process Architecture (BPA) modeled using Riva method and modified using the BPAOnt Ontology by Yousef et. al. [1]. First this work extends the current BPAOnt Ontology before drawing information from it and then semantically represents the artifacts of the EIA based on both the BPAOnt and problem domain process Ontologies. Using a case-study approach, business process architectural elements of a banking organisation have been used.