The necessity for established, well-defined parish boundaries was identified at the Council of Trent (1545-1563) as a way to protect pastors and their communities from the harm that evolved from uncertain lines of authority and property. The original trouble was grounded in the feudal system: In earlier times the church was by no means separate from the state, as it is in most countries today. The notion of a parish with canonically (that is, by church law) protected rights and responsibilities serves to clarify what you and I “get”—and have a right to—when we join up.
Parish boundaries aren’t always geographically defined. Most are designated by territory, but they can also be defined by language, rite, ethnicity, or other elements that serve the community. For example, in large U.S. cities a French or Korean parish might serve all who speak those languages primarily. There’s also a military diocese that encompasses U.S. service folk wherever they may be, creating parishes anywhere armed forces personnel are serving. Rites in communion with Rome, like Maronites, Melkites, Ukrainians, and others, establish parishes defined less by geography than by the particular liturgy customary for those communities.
As a Catholic you may worship freely in any of these parishes or all of them if you wish. But there are advantages to registering with a particular parish—whether or not you live inside its technical boundaries—that are worth considering. A parish is defined by four basic elements.
First, it stands to serve a certain segment of the People of God. Second, it’s administered by a priest specifically charged with its sacramental care (even a parish with a nonordained administrator on-site reports to a member of the clergy who holds the official title of pastor). Third, a parish is governed by church law which outlines reciprocal rights and duties of pastor and parishioners. Finally, a parish is guaranteed a suitable site containing all that’s necessary for the Catholic spiritual life: Eucharistic equipment, baptismal font, confessional, cemetery, and a place for sacramental records to be kept. Those who register with a particular parish will have full access to all that’s necessary for Catholic identity when the time comes. Trust a former parish secretary here: Get on the books. It makes your sacramental life easier!
• 1 Corinthians 1:10-17; 12:1-31; Ephesians 2:19-22; 4:1-7, 11-16
• See nos. 26-27 of Pope John Paul II's 1988 Apostolic Exhortation Christifideles Laici
• Parishes Online lets you find websites, Mass times, and directory information for any parish or diocese in the U.S.
• Excellent Catholic Parishes: The Guide to Best Places and Practices by Paul Wilkes (Paulist Press, 2001)
• The Church: The Evolution of Catholicism by Richard P. McBrien (HarperOne, 2008)