One who was to the east and had told his son, ‘‘Make an eruv for me in the west’’; to the west and had told his son, ‘‘Make an eruv for me in the east’’ — if the distance from him to his house is two thousand cubits and to his eruv more than that, he is permitted [the techum of] his house but forbidden [the techum of] his eruv; if to his eruv is two thousand cubits and to his house more than that, he is forbidden [the techum of] his house but permitted [the techum of] his eruv. One who places his eruv in the extension of a town has accomplished nothing. If he placed it beyond the techum, even one cubit, whatever he gains he loses.

The residents of a large town may traverse an entire small town, but the residents of a small town may not traverse an entire large town. How so? One who was in a large town and placed his eruv in a small town, [or] in a small town and placed his eruv in a large town, may traverse its entirety and two thousand cubits beyond it. But R’ Akiva says: He has no more than two thousand cubits from the place of his eruv.