The Roman Catholic nationality Parishes of Meriden, Connecticut served their respective immigrant populations in assimilating and Americanizing throughout the course of their development, starting in the early nineteenth through to mid-twentieth century. The development of each parish allowed immigrants to create their own support network, practice their unique cultural and religious beliefs, distinguish themselves from other immigrant groups, and ultimately assimilate into one community. By forming into seven different parishes, combined with an overall reduction in religious participation across modern American society, church resources have been stretched. As a result, the nationality parishes have recently been shut down or combined with other parishes by the Archdiocese of Hartford to conserve resources and to minister to the current needs of the communities where they exist. For many Catholics in the Archdiocese, this has been a difficult transition, as they have had to move away from their traditional church buildings and specific customs. This thesis combines a study of the secondary literature on nationality parish formation across the Northeastern United States with a study of parish histories, local histories, demographic and material studies to create a narrative of the formation of the Roman Catholic nationality parishes in Meriden. This thesis contends that the nationality parishes no longer fill a once necessary function, and in order for the church to meet the needs of its communicants, it must reform. Understanding the origins of the parishes in Meriden and their intended purpose could shed light on the necessary but uncomfortable transition, as well as assist the church throughout the state and region in meeting the needs of its newest, non-European, immigrant members.