Reshus Harabim in a Modern City
The central question in a large-city eruv is often whether its streets are a reshus harabim. If they are, the ordinary poles and wires used around a karmelis are not enough under the halacha followed by the Alter Rebbe. Brooklyn therefore has to be considered as a city before any neighborhood route is considered as a boundary.
Width, openness, and public use
A reshus harabim is a public way with the width and form discussed by Chazal and the Rishonim. Sixteen amos is the classic width. The route's openness, whether it is mefulash, the freedom of public access, and its place in the city network enter the definition.
The familiar tests do not operate as an informal checklist in which one favorable feature removes all the others. Their application depends on the walls around the city, the form of the road, and the view of the poskim followed in the psak.
Shishim ribo
Many Rishonim require public use corresponding to the six hundred thousand who travelled in the midbar. The disagreement does not end with the number: one must decide whether it describes passage through a single point, the population using the roads of a city, or another measure of regular public movement.
The Alter Rebbe brings the shishim-ribo definition and also the stricter view that does not require the number. In his discussions of the desert camp and city roads, the population and the network that serves it cannot be reduced automatically to a counter on one block.
“There is no reshus harabim today”
The expression arose in cities whose narrow or crooked streets, gates, walls, and populations often failed to meet the demanding definition of a Torah public domain. It is a halachic position tied to those conditions, not a permanent description of every later city.
New York has millions of residents, a continuous public grid, wide avenues, bridges, tunnels, and unrestricted travel between neighborhoods. The older phrase has to be applied to those facts through psak; it cannot be used in place of them.
Rav Moshe and New York
Rav Moshe Feinstein treated the New York question across decades. His early teshuvos examine Manhattan's population, streets, walls, bridges, and the effect of public carrying on visitors. His later teshuvos reject reports that he had permitted an eruv in Flatbush and continue the large-city analysis for Brooklyn.
In 5739, Rav Moshe signed a direct ruling that no eruv should be established in Brooklyn because he regarded it as a reshus harabim de'oraisa. Public proclamations by leading Rabbonim applied the same large-city concern beyond Manhattan.
Crown Heights inside Brooklyn
Crown Heights is not separated from Brooklyn's public ways by gates or municipal walls. Eastern Parkway and the surrounding avenues feed the same open street and transit network used by the borough and the city.
The Crown Heights Beis Din's rulings give the direct practical psak for the neighborhood. The reshus-harabim pages explain one of the major halachic settings behind that prohibition.