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How a Contentious Halachic Principle Has Shaped the Nature of Eruv



Jewish communities past and present have striven to erect an eruv to permit carrying outdoors on Shabbat. The familiar type of eruv involves surrounding the area with a series of rudimentary doorframes (tzurat ha’petach, often taking the form of poles with wire running across the tops). This type of enclosure, however, is only effective in a karmelit – an area where hotza’ah is only rabbinically forbidden.(1)

In a reshut ha’rabbim, a true public domain where hotza’ah is biblically proscribed, only actual doors permit carrying (Eruvin 6; Shulchan Aruch, Orach Chayim 364:2).(2) It is usually highly impractical to install doors to block off streets; indeed, the vast majority of eruvin nowadays are comprised of tzurat ha’petach. Obviously, the assumption behind these eruvin is that the streets they enclose only have the status of karmelit.

But is this truly the case?

The Tosefta defines a reshut ha’rabbim simply as “a main street, large plaza, or alleyways that are open on both sides” (Shabbat 1:2); the Gemara adds that it must be at least 16 cubits (roughly 25 feet) wide and unroofed (Shabbat 98a, 99a). Based on a simple reading of the Talmudic sources, nearly all contemporary streets should be considered reshut ha’rabbim!

The Geonim, however, mention an additional criterion for a true reshut ha’rabbim: the area must have a population of 600,000 (Halachot Gedolot Aspamya, Hilchot Eruvin; Geonic Responsa Sha‘arei Teshuvah 209). Although this principle is not mentioned explicitly in the Talmud, it does follow the general Talmudic model that the parameters of forbidden labor of Shabbat are to be derived from the construction of the Tabernacle. In the case of hotza’ah, the materials for the Mishkan were transported through the pathways of the desert encampment, which were not only 16 cubits wide and unroofed as noted in the Gemara, but also served a population of 600,000.(3)

Numerous Rishonim, notably Rashi throughout his commentary on the Talmud, accept this Geonic tradition. In fact, Tosafot finds a hint to the criterion of 600,000 in the Talmud itself (Shabbat 6b s.v. kan). The Gemara states that the desert was a reshut ha’rabbim only when the Jewish people traversed it following the Exodus. According to Tosafot, the fact that the desert lost its status as a reshut ha’rabbim as soon as it no longer housed the Jewish people – which numbered 600,000 at the time –

“somewhat implies” that an area requires a population of that size in order to be considered a reshut ha’rabbim. This deduction is clearly not ironclad; in any event, this passage is the only possible allusion to the Geonim’s opinion within Talmudic literature.

Unlike Tosafot, the Ramban finds it unconscionable that Chazal could have neglected to mention such a fundamental rule explicitly (Shabbat 57a, Eruvin 59a). Indeed, the Rif and Rambam make no mention of the Geonic tradition, and several Rishonim follow the Ramban in rejecting it outright. These Rishonim rule that any public thoroughfare that is uncovered and 16 cubits wide is a reshut ha’rabbim regardless of population.

The demographics of ancient cities also pose a challenge to the idea that only a place with 600,000 people is a reshut ha’rabbim. The Talmud states that Jerusalem and Machoza (a Babylonian city) would have been considered reshut ha’rabbim if not for the fact that the city gates were closed at night (Eruvin 6b). Is it plausible that these cities had populations of 600,000 in the Talmudic era?

According to some traditional sources, the answer seems to be yes. The Midrash states there were over 1.2 billion people celebrating Passover in Jerusalem when the second Temple stood (Eichah Rabbah 1:1). Furthermore, Josephus (lehavdil) writes that the Romans killed 1.1 million Jews during their conquest of Jerusalem in 70 C.E. (The Wars of the Jews 6:9:3). (See also Gittin 57b-58a regarding Beitar.)

These figures, however, were probably not intended to be factually precise. Even today, when the area of Jerusalem is many times greater than in the second Temple era, and the apartment houses are much larger, the population stands at less than 1 million. Historians estimate that the population of Jerusalem just prior to the destruction of the Temple was about 80,000 (see Even if this assessment is too low (especially given the fact that many pilgrims who were not regular residents flocked to Jerusalem [cf. Ritva, Shabbat 6a]), the population could not have been anywhere near that of Rome, which was by far the largest city in antiquity, “perhaps reaching 1,000,000 inhabitants. No city was as large until the Industrial Revolution” (

Many, of course, will argue that halacha discounts academic findings. It is the tradition of the Jewish people that matters, and the fact that the Geonim and many (probably most) Rishonim endorse the 600,000 standard demonstrates that divine providence has orchestrated its inclusion in the halachic canon.

Even within halacha, however, it is unclear whether the Geonic tradition should be considered normative. The Shulchan Aruch mentions both opinions (Orach Chayim 303:18, 354:7), and the commentators debate which opinion he considers primary. Although several Acharonim have argued forcefully for the stringent opinion (most famously, Mishkenot Yaakov, Orach Chayim 119-122), the clearly accepted tradition, at least among European Jewry, was to rely on the criterion of 600,000 (see Hilchot Shabbat beShabbat 63:44). Indeed, a common refrain amongst the poskim is “we have no reshut ha’rabbim nowadays.”(4)

Today, however, that statement may no longer be operative. In the 19th century, urban areas began to grow rapidly, and the population of many cities sprouted past 600,000 (see Aruch HaShulchan, Orach Chayim 303:21, 345:18). Nowadays, numerous metropolises easily meet the criterion of 600,000 people and would be considered reshut ha’rabbim even according to the lenient opinion, obviating the possibility of a doorframe eruv.(5)

Although we are dealing here with the possibility of Shabbat violation on a biblical level – one of the most severe sins – the extreme hardship that the absence of an eruv causes has motivated many city-dwelling Jews to seek halachic justification for eruvin of tzurat ha’petach even in contemporary metropolises. In order to permit a doorframe eruv even in large cities, some authorities have interpreted the Geonim’s opinion as maintaining that a thoroughfare is only a reshut ha’rabbim if 600,000 people traverse that particular street daily.(6)

Superficially, this interpretation can be supported by the language of such prestigious sources as Halachot Gedolot Aspamya and Shulchan Aruch (op. cit., see also Tosafot Rabbeinu Peretz, Eruvin 6a s.v. keitzad). Nevertheless, it is extraordinarily difficult to accept. The vast majority of sources state clearly that the figure of 600,000 refers to the number of people in the city or area, not to the number of travelers on one road (cf. Mishnah Berurah 345:24).

Similarly, the notion that only a thoroughfare with daily traffic of 600,000 is a reshut ha’rabbim only compounds the historical difficulty with the Geonic tradition (see Responsa Achiezer 4:8; Aruch HaShulchan, Orach Chayim 345:18). In ancient times, it was at least theoretically possible for a city’s population to reach 600,000 (as was apparently the case in Rome). No ancient street, however, accommodated such a burden of traffic in one day. Even today, there is virtually no street in the world that meets this criterion (see Responsa Shulchan HaLevi 11:1).

In a novel approach, Rav Moshe Feinstein adopts a compromise view that allows for a doorframe eruv in most contemporary cities (Iggerot Moshe, Orach Chayim 1:139, 4:87-88). R. Moshe writes that the figure of 600,000 refers neither to the population of the city as a whole nor to a single road; it refers to the number of people who are out and about on all the city’s streets. For this to be the case, R. Moshe estimates that the total population of the city (including visitors) must be about 3 million. Furthermore, R. Moshe maintains that this population must be within a 12 mil by 12 mil area, which was the size of the Jewish encampment in the desert.

Based on his original ruling, R. Moshe opposed an eruv in the extremely densely populated boroughs of Manhattan and Brooklyn;(7) those who oppose an eruv in London maintain that R. Moshe’s opinion would forbid an eruv there as well. Indeed, tensions about eruvin seem to run highest in these three locations – despite the fact that R. Moshe himself writes that one should not protest those who erect an eruv in locations that he forbids (Iggerot Moshe, Orach Chayim 4:89; although see Ma’yan Beit HaShoeva p. 234).

Due to the role his opinion plays in the fierce eruv controversies in Manhattan, Brooklyn, and London, people tend to perceive R. Moshe as a machmir in eruvin. In truth, R. Moshe’s opinion is a leniency, as the simple reading of the normative poskim indicates that 600,000 refers to the total population of the city, not merely those out on the streets. By the classical definition, many modern metropolises qualify as reshut ha’rabbim.

Similarly, R. Moshe’s limiting the physical area in which the 600,000 must be located to 12 square mil has no support in the classical sources. One gets the impression from the early poskim that however large a city is, its streets are a reshut ha’rabbim if its population is 600,000. Unlike R. Moshe’s approach, however, the classical opinion is very difficult to apply to the contemporary world.

Defining a “city” was not difficult in ancient times. Cities were often walled; if not, the buildings of the city ended abruptly and gave way to empty land until the next city. In the United States and elsewhere, metropolitan areas often consist of vast swaths of uninterrupted settlement subdivided into various municipalities.(8) What is considered a halachic “city” in which the population of 600,000 must be located?

Suggesting that the 600,000 must be located within municipal boundaries leads to a bizarre conclusion. Consider the following example: There is no physical demarcation whatsoever between the New York City borough of the Bronx (pop. 1.4 million) and the separate municipality of Yonkers (pop. 200,000). It seems absurd to suggest that by merely crossing the street from the Bronx into Yonkers, one exits reshut ha’rabbim territory and enters karmelit territory.

It is much more palatable to assume that municipal borders are halachically irrelevant and that the defining characteristic of a “city” is contiguous settlement (as it is for techum Shabbat). However, this approach is also difficult. New York’s suburbs in northern New Jersey are physically disconnected from New York City by the Hudson River, and thus could reasonably be a karmelit even if New York is a reshut ha’rabbim. These suburbs consist of many adjacent municipalities, none of which has a population of 600,000 on its own; the contiguous settlement, however, has a population which easily exceeds 600,000.

If municipal boundaries are halachically insignificant, one could argue that the streets of a relatively small town such as Teaneck should be viewed as serving the entire interconnected metropolitan area of northern New Jersey. According to this approach, a doorframe eruv would be completely forbidden in the Teaneck even according to the lenient definition of reshut ha’rabbim. This approach is counterintuitive, though. When the Rishonim referred to “a city of 600,000,” they probably had in mind a densely populated metropolis, not a vast suburban expanse (cf. Ran on the Rif, Shabbat 26a s.v. aval; Piskei Riaz, Eruvin 1:5).

The formulation of R. Efraim Zalman Margaliot could potentially set us on the right track to solve this dilemma: A reshut ha’rabbim must be “prepared as a path for 600,000 people located nearby, who come and go in the area regularly to the extent that it would be possible for all of them to traverse in one day” (Responsa Beit Efraim, Orach Chayim 26). Nevertheless, a satisfying, precise way to apply the standard of 600,000 to the layout of contemporary metropolitan areas remains elusive.

Even if suburban areas do not fulfill the criterion of 600,000, it would still be preferable not to rely on an eruv of tzurat ha’petach there, since the Mishnah Berurah urges a halachically punctilious individual (ba‘al nefesh) to follow the opinion that any 16-cubit-wide thoroughfare is a reshut ha’rabbim regardless of population (345:23, 364:8). It seems clear, though, that densely populated urban areas do fulfill the criterion of 600,000 people according to the classic understanding. As such, one should not carry in such a place even if one is not particularly halachically scrupulous.

Nevertheless, the fact remains that several great halachic authorities have permitted eruvin even in urban areas, based on the novel interpretations of the 600,000 principle mentioned above, as well as other halachic considerations that are beyond our present purview.(9) While it is debatable whether it is proper to build an eruv in such a locale, one should not forcefully protest and rebuke those who rely on it once it has been erected.


  1. The Rambam, however, maintains that an eruv must always consist mostly of actual walls or fences (Hilchot Shabbat 16:16).
  2. Some poskim rule that a tzurat ha’petach suffices to permit a reshut ha’rabbim on a biblical level; doors are only required on a rabbinical level. If one accepts this ruling, there is much more room to err on the side of leniency, because an area surrounded by doorframes will at worst be subject to a rabbinic prohibition. Many, however, maintain that without doors, the biblical prohibition of reshut ha’rabbim remains (see Bei’ur Halacha on 364:2).
  3. Tosafot notes that the census in the desert from which this number is derived includes only males between the ages of 20 and 60; the total population was much greater. Yet, for halachic purposes, we only use figures that the Torah mentions explicitly (Eruvin 6a s.v. keitzad). Cf. Responsa Rivash 405.
  4. It is interesting to note that the Talmud Yerushalmi quotes an opinion that “a reshut ha’rabbim must run straight from one end of the world to the other,” and “there is no reshut ha’rabbim in this world, only in the next world” (Eruvin 8:8). This was clearly not normative, though – the voluminous discussions of reshut ha’rabbim in the Talmud make clear that it was a very real aspect of life. Our Sages even suspended the performance of the mitzvot of shofar, lulav, and Megillah on Shabbat for fear that people may mistakenly carry these items in a public domain (cf. Bei’ur Halacha 345 s.v. she’ein).
  5. Rabbi Mendel Poliakoff, who studied at the Telshe yeshiva in Lithuania and later served as a rabbi in Baltimore, attacks those who oppose eruvin as not following in the true mesorah of European Jewry where eruvin were unquestionably accepted (Minhagei Lita pp. 74-6). He ignores, though, the fact that eruvin in contemporary cities may run afoul of the 600,000 criterion, whereas those in prewar Eastern European towns certainly did not.
  6. Some poskim have further argued that those traveling in cars, which constitute a separate domain, cannot properly be considered to be traversing the street and therefore do not count towards the tally of 600,000 (see Rabbi Chaim Jachter, Walking the Line, p. 15). However, this calculus is irrelevant according to those who maintain that 600,000 refers to the population of the city – the issue is the number of people the road serves, not the number of people who actually tread on it.
  7. An analysis of whether R. Moshe’s calculations were correct is beyond the scope of this article. It is noteworthy that R. Moshe permitted an eruv in Kew Gardens Hills although Queens has a larger population than Manhattan (Iggerot Moshe, Orach Chayim 4:86). R. Moshe does not clearly state why Kew Gardens Hills should be considered separate from the rest of Queens.
  8. Compare this to contemporary Israel – besides in Gush Dan – where cities and towns are often clearly distinct.
  9. See an excellent summary in Rabbi Baruch Simon’s Imrei Baruch. In any event, any posek who permits a doorframe eruv on today’s city streets must have a cogent explanation as to why the roads he permits are less likely to be reshut ha’rabbim than thoroughfares in the times of Chazal (see Shulchan Halevi 11:1).

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Rabbi Yaakov Hoffman leads Washington Heights Congregation (“The Bridge Shul”). He is a member of the Kollel L’Horaah of RIETS and has had a lifelong interest in the history of halacha. He can be reached at