Inspired by Is Juneau, Alaska -- surrounded by natural barriers -- a natural eruv

Is there a maximum square mile or square kilometer area that may be enclosed by an Eruv? (sources)

  • I suspect that the size is relevant to the Juneau question, which is why I gave land-mass details, but also noted that most of the land is itself on an island, while the downtown area is in a smaller coastal area on the mainland. I believe that there are limits for an island -- I think you need to be able to see it all from a certain distance, but I'm not sure whether that could be from a mountain. Feb 18, 2013 at 17:51

1 Answer 1


R Moshe Feinstein (Igrot Moshe OC 1:139:6) rules that according to the Ritva and Ramban the maximum size of a Reshut HaYachid (and hence the maximum size of an Eiruv) is as far as the eyes can see, which he understands, based on Bechorot 54b, to be 16 mil in either direction which would be 32x32 mil which is roughly 1000 km^2 or 250K acres. (For reference the area of Manhattan is only 87 km^2.)

  • Does this imply that Rav Moshe held of the Manhattan Eiruv? I'm asking out of ignorance Jul 29, 2019 at 22:21
  • 1
    @Shoel I don't understand how this would imply that
    – Double AA
    Jul 29, 2019 at 22:29

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