Parish

A parish is the area which is served by a church. This term is used by these churches: Church of England and the Anglican Communion, Roman Catholic, the Eastern Orthodox Church, Lutheran churches, and some Methodist, and Presbyterian churches. The idea is that the local priest or minister is responsible for the 'souls' in the parish.
The term refers to a local church community or territory, including its main church building, and other property. The word 'parish' is also used more generally to refer to the collection of people who attend a particular church. In this usage, a parish minister is one who serves a congregation.
A parish is a subdivision of a diocese or 'see'. The diocese is headed by a Bishop.
Parishes were responsible under the English Poor Law for supporting the poor people of their parish. Charles Dickens described how this worked. The parish would employ a beadle who would manage the workhouse. This work was later taken over by the board of guardians, who were not part of the church.
Local government.
In some countries a civil parish is an administrative area of local government. Usually they started as an church parish of the same name. In the course of time, perhaps with modified boundaries to better suit local government, the parish survives.
In the American state of Louisiana, a parish is an administration area similar to a county.