Membership in a parish and registering at a parish are not the same thing, although they are often spoken of interchangeably. A "parish" consists of a geographical area with clearly defined boundaries, which has its own church or chapel belonging to it and its own pastor administering it. Any Catholic who lives within the physical boundaries of a parish is automatically considered a "member" of that parish for purposes of administering the sacraments. He/she cannot be refused the sacraments by the pastor of the parish in which he/she resides unless the pastor has a valid canonical reason to do so. For example, when a Catholic marries, the pastor of the parish within whose boundaries he/she resides has a responsibility to witness the marriage, unless there is a valid canonical reason for him to refuse (e.g., the person is already validly married to another spouse).

 

Being registered at a parish is different. One becomes registered at a parish when one fills out a census form, regularly contributes to the parish's finances, or otherwise "signs up" at the parish. Registering is primarily useful for administrative purposes. Keeping a parish registry allows pastors and administrative staff to keep track of who is worshipping at the parish and contributing to the parish's financial needs. However, a pastor is not required to provide "one-time" sacraments, such as marriage or baptism, to a registered person who is not a geographical member of the parish.

 

Registering at a parish has a lot of great benefits, including having one's contact information on record at the parish and being able to receive important communications, having an established sacramental record, and receiving offertory envelopes, which make it easier to keep track of contributions.

 

Here are some interesting articles on the historical development of parishes and on the difference between parish membership and registration.