961. Making a Shittuf for a City

Eiruvin 5:19

A shittuf in a city is made as follows: Every courtyard makes its own eiruv so that the children will not forget the concept of eiruv. Next, all the residents of the city participate in a shittuf together the same way that a shittuf is made for an alley. If the city had formerly been the property of a single person, even if it subsequently became the property of many people, all the residents may join together in one shittuf, which will enable them to carry throughout the city. Similarly, even if a city is owned by many people, if it has just one entrance, all the residents may make a single shittuf together.

Eiruvin 5:20

However, if a city was originally the property of many people and it has two points of access, then the city as a whole may not make an eiruv, even if it later becomes the property of one person. Rather, some area is excluded; this could even be one house in one courtyard. A shittuf may then be made for the rest of the city. All the people who participate in the shittuf may carry throughout the entire city with the exception of the place that was excluded. If many people live in that place, they may carry there if they make their own shittuf, though they may not carry in the rest of the city.