Most poskim maintain that Brooklyn is not classified as a reshus harabbim because of the following three reasons:
- As Brooklyn is circumscribed by more than three mechitzos at its waterfront, it is fundamentally a reshus hayachid.
Even one of the above conditions would be sufficient ground to permit an eruv of tzuras hapesachim. Additionally, as there are many reasons to allow an eruv in Brooklyn, even a Baal Nefesh can utilize the eruv with certainty. Furthermore, since Brooklyn is bounded on three sides by mechitzos, any eruv in Brooklyn would be considered a Rambam eruv.