This chapter will attempt to shed light on the relevant explanations for designating or creating urban agglomeration for the purpose of administration and governance in the case of largest urban space in Jamaica. The main objective of this chapter is to provide an in-depth look at the case of Portmore with specific emphasis on the socio-economic, political, legislative, and relevant policy arrangements that influence the change in sub-national geo-political status from municipality to parish. The researchers explore the literature on local government reform, public financing, urban economics, and urban planning which provided a basis for objectively interrogating the proposed change. From the analysis of existing legislations, policies, and international conventions such as the New Urban Agenda, the proposal to change the geo-political designation of the Municipality of Portmore raises several questions about the economic profile of the area and the capacity to enjoy the benefits of urban agglomeration given its location attributes. Understanding the evolution of the theoretical discourse in urban planning can provide clarity on the relevance of this geo-political designation, the intergovernmental relationship associated with the geo-political designation, particularly as it relates to autonomy, and the allocation of resources for the provision of local government services. This understanding will help to direct the decision makers as to the best designation for Portmore given its current realities and importance of implementing measures to support decentralization and autonomy at the local level for major urban areas. The researchers found that the economic viability of the proposition is at best questionable as the economic base of the municipality is limited and its capacity to generate linkages demand serious considerations. Attention should be given to local government reform in the face of emerging trends and current realities rather than changing status of an urban areas which is the direct result of the principles of urban agglomeration.