This, from a source. A letter to Bishop Skylstad, president of the USCCB, on how some US dioceses might have been misusing canon law. Or mistakenly interpreting it, shall we say:

Congregation for the Clergy

Prot. N. 20060481

The Most Rev. William Skylstad

President of the United States Conference of Catholic Bishops

3211 Fourth Street NE

Washington DC 20017-1194

U.S.A.

Your Excellency,

This Congregation deems it opportune to write to you regarding the closure of parishes in the dioceses of the United States, since in recent times certain dioceses have wrongly applied canon 123 CIC and stating that a parish has been “suppressed” when in reality it has been merged or amalgamated.

A parish is more than a public juridical person. Canon 369 defines the diocese as a “portion of the people of God which is entrusted to the bishop to be nurtured by him”. Similarly, “A parish is a certain community of Christ’s faithful, stably established within a particular Church, whose pastoral care, under the authority of the diocesan bishop, is entrusted to a parish priest as its proper pastor (cf. can. 515).”

In this light, then, only with great difficulty, can one say that a parish becomes extinct. A parish is extinguished by the law itself only if no Catholic community any longer exists in its territory, or if no pastoral activity has taken place for a hundred years (can. 120 #1). When a parish is “suppressed” by competent authority in reality the still existing community of Christ’s faithful is actually “merged” into the neighboring community of Christ’s faithful and constitutes a larger community, and the territory of the extinguished parish is added to the other, forming a larger territorial unit. While the parish church and the physical parish plant may be closed and the name of a particular parish extinguished, the spiritual needs of the portion of the Faithful which once constituted that parish, must continue to be provided for in accord with their rights in law.

In the case where the portion of the Christian Faithful is reallocated among pre-existing or newly created parishes, the corresponding patrimony and obligations of the closed parishes must follow the Faithful in an equitable and proportionate fashion in accord with the corresponding responsibilities and pastoral duties assumed by the parishes ad quem. The wishes of any existing founders and benefactors must be respected, as must any acquired rights as expressed in canon 121 or 122.

Often when a bishop calls his action a “suppression” it is in reality a merger of two communities of Christ’s faithful. Thus canon 121 applies: “When aggregates of persons or of things which are public juridic persons, are so joined that from them one aggregate is constituted which also possesses juridic personality, this new juridic person obtains the patrimonial goods and rights proper to the previous aggregates….” The “suppression” of a parish is in most cases then a “unio extinctiva”. If a parish is divided between more than one existing parish then can. 122 would apply.

Thus the goods and liabilities should go with the amalgamated juridic person, and not to the diocese. This would also seem to be more consonant with the requirement that the wishes of the founders, benefactors and those who have acquired rights be safeguarded, In most cases “suppressions” are in reality a “unio extinctiva” or “amalgamation” or “merger” and as such the goods and obligations do not pass to the higher juridic person, but should pertain to the public juridic person which remains or emerges from the extinctive union. The goods and liabilities should go to the surviving public juridic person, that is the enlarged parish community.

In conclusion, this Congregation notes that the erroneous use of can. 123 in the dioceses of the United States is not uncommon and therefore asks Your Excellency to bring this matter to the attention of the individual bishop members of the Episcopal Conference.

I take this opportunity to renew my sentiments of esteem and with every best wish, I remain,

Yours sincerely in Christ,

/s/ Dario Card. Castrillon-H.

/s/ Csaba Ternyak

Bolded paragraph my emphasis.
(Examples of a properly “suppressed” parish would be, say one in an area where the population had died out completely or near to it – in some areas in the Great Plains, for example. I think.)