965. Placing One's Eiruv 1,000 or 2,000 Cubits Away

Eiruvin 6:3

If a person places his eiruv 1,000 cubits east of his house in a city, he may walk 2,000 cubits to the east of his eiruv on Shabbos. He may also walk 2,000 cubits to the west of his eiruv, which would be 1,000 cubits from the eiruv to his house and another 1,000 cubits further west from his home. He may not traverse the city beyond these 1,000 cubits. If there are fewer than 1,000 cubits from his home to the edge of the city, even if his Shabbos boundary ends just one cubit beyond the city, then the whole city is treated as if it were only four cubits (about six feet) and he may continue another 996 cubits further.

Eiruvin 6:4

Accordingly, if one placed his eiruv 2,000 cubits east of his house, he would lose the ability to walk the entirety of the city to the west. He would be able to walk 2,000 cubits from his house to his eiruv and then an additional 2,000 cubits beyond his eiruv. In this scenario, one may not walk even a single cubit to the west of his house. If a person places his eiruv in a private domain - even in a huge city like Nineveh, the ruins of a city or a cave that is suitable for use as a dwelling - he may walk the entirety of this domain plus 2,000 cubits beyond it in every direction.