877. Cities Near One Another

Shabbos 28:4

These buildings are not added to a city's measurements: a structure with two walls and no roof, even if people live in it; a bridge, grave, shul, idolatrous temple and a storehouse that do not have living space; a well, trench, cave, bird coop, and a house on a boat.

Shabbos 28:5

If the distance between two cities is no more than 141 1/3 cubits - i.e., 70 cubits and change from each city - they are treated like a one big city. Accordingly, the residents of each city can walk throughout the other city plus 2,000 cubits beyond it. Let's say that three towns are arranged in a triangle. If there are 2,000 cubits or fewer between the town in the middle (B) and both towns on the outside (A and C), and there are no more than 282 2/3 cubits between the two towns on the outside - so that if the middle town (B) were on the direct line from A to C there would be no more than 141 1/3 cubits between it and each of them - then they are all treated like one big city. When the Shabbos boundary is measured, it is measured 2,000 cubits in all directions from these three towns combined. If a city wall was built before the city was settled, the Shabbos boundary is measured from the residences; if the city was settled first and then surrounded by a wall, the boundary is measured from the wall.