The Sages said: “A walled city and all that adjoins it (samukh) and all that is visible with it (nir’eh imo) are reckoned as a walled city” (Megilla 3b). Therefore, not only do the residents of the Old City of Jerusalem celebrate Purim on the fifteenth of Adar, but so do the residents of all the neighborhoods adjacent to the Old City. Even though the city has expanded greatly over the years, each and every neighborhood takes on the status of the Old City and reads the Megilla on the fifteenth, since each one is adjacent to the one next to it.
While the neighborhoods of Jerusalem were still being built, a question arose regarding the status of neighborhoods that were originally built far away from the rest of the city. Most recently, this question came up regarding the neighborhoods of Ramot and Har Nof. Some authorities maintain that only neighborhoods to which there is a continuous stretch of houses from the Old City are considered part of Jerusalem. If, however, there is a gap of 141 and one third amot (67.8 meters) between the two areas, they are considered separate locations. Accordingly, these authorities ruled that residents of Ramot and Har Nof must read the megilla on the fourteenth.
Others maintain that all neighborhoods that are considered part of the Jerusalem municipality for tax purposes – and all the more so if they are surrounded by the same eruv – take on the status of Jerusalem and read the Megilla exclusively on the fifteenth. Thus, they ruled that residents of Har Nof and Ramot must read the Megilla on the fifteenth. The former Chief Rabbis of Jerusalem, R. Shalom Messas and R. Yitzĥak Kulitz, ruled in this manner, and this is the prevalent custom. All of these rulings were decided, over time, as Jerusalem expanded. With the help of God, Builder of Jerusalem, the city will continue to be built up, and even the furthest neighborhoods eventually become adjacent and linked to the rest of the city, until it becomes clear to all that they are considered part of Jerusalem.
In contrast, Rambam maintains that even a place from which a walled city can be seen is not considered part of the city if it is more than a mil away. The only distinction is that when the city is visible, we measure the mil as the crow flies, and when it is not visible, we measure it by a straight, terrestrial line (Maharitatz §120). Alternatively, when the city is visible, we measure a mil; and when it is not visible, the nearby place takes on the status of the walled city only if it truly adjacent – on the outskirts of the city (Maharam Alashkar). That is, if there is a distance of 70 and two thirds amot between the two places, and the walled city is not visible, they are considered separate places. And if there are two neighborhoods, the distance is doubled – 141 and one third amot. Ran, Roke’aĥ, and Ohel Mo’ed concur. The Aĥaronim disagree about the opinion of sa 688:2. According to ma and others, sa agrees with Rashi and most Rishonim. Pri Ĥadash and others claim that sa concurs with Rambam.
The reason that places adjacent to or within view of a walled city take on the status of the city is that they are subordinate to and reliant on it. This can be inferred from the words of Ritva, who writes that residents of these places come to take refuge within the city’s walls in times of danger. Turei Even 3:2 and Ĥatam Sofer, oĥ 193 explain that the reason is in order not to separate between people who live close to each other.
Practically speaking, mb 688:6 and sht ad loc. 7 maintain that the first opinion is the primary one. Yabi’a Omer 7:58-59 states that one should take the second opinion into consideration as well, especially since residents of walled cities can satisfy their obligation, be-di’avad, by reading the Megilla on the fourteenth.
How exactly do we measure the distance between a walled city and a place that can be seen from it? Some maintain that we measure only from areas that are actually walled (Yabi’a Omer 7:59:1), while others maintain that the measurement begins from the edges of the expanded city. Another dispute concerns whether the residents of the place need to be able to see all – or at least most of – the walled city (this appears to be Me’iri’s position, and R. Ĥayim Palachi writes this explicitly), or if it is sufficient for them to be able to see a small part of the city (Maharil Diskin, Mikra’ei Kodesh [Frank] §24)?
In practice, the former Chief Rabbis of Jerusalem, R. Shalom Messas (Shemesh U-magen 1:51-52, 2:16-17) and R. Yitzĥak Kulitz, maintained that all neighborhoods that are part of Jerusalem for the purposes of paying municipal taxes read the Megilla exclusively on the fifteenth. They ruled this way even for the residents of Ramot and Har Nof. R. Shlomo Zalman Auerbach concurs. Moreover, in his opinion, the outlying areas would read the Megilla on the fifteenth even if they were separate entities for tax purposes, because there is an eruv that connects these neighborhoods to the city of Jerusalem (Halikhot Shlomo 20:8-9). These authorities also relied on the majority opinion of the Rishonim, who maintain that “adjacent and visible” is measured from the farthest outskirts of the expanded city. Kaf Ha-ĥayim 688:10 suggests a novel idea: that the definition of a mil is the amount of time it takes to travel a mil; R. Messas mentions this suggestion as additional support for his ruling. My teachers, R. Avraham Shapiro, R. Mordechai Eliyahu, and R. Shaul Yisraeli, also endorsed, in practice, the halakhic determination that all neighborhoods of Jerusalem should read the Megilla on the fifteenth, with a berakha (Mikra’ei Kodesh [Harari] 5:11 and n. 43).
In contrast, several great authorities maintain that the rule is as follows: Any neighborhood within a mil of the wall itself reads on the fifteenth, even if the entire area in between is empty. However, when measuring from a point in the expanded city, an empty area of 141 and a third amot constitutes a gap between Jerusalem and that neighborhood, and thus its residents must read on the fourteenth, with a berakha. This is the opinion of Yabi’a Omer 7:58 and Or Le-Tziyon 1:45. Ĥazon Ish 153:2-3 and Mikra’ei Kodesh (Frank) §23 also rule similarly, but they ruled that the residents of Giv’at Sha’ul should read the Megilla on the fifteenth, despite the fact that hundreds of meters of undeveloped land separated between that neighborhood and the rest of the city at the time. Apparently, they ruled this way because the residents of Giv’at Shaul were dependent on the city for all their affairs. Minĥat Yitzĥak 8:62 ruled that the residents of Ramot should read the Megilla on the fourteenth. The same is reported in the name of R. Yosef Shalom Elyashiv. Several years later, however, when Ramot expanded, R. Elyashiv changed his ruling and instructed residents of Ramot to read the Megilla on the fifteenth (even though there is an undeveloped area of more than 141 and a third amot between it and the main part of the city).
A bigger question arose regarding Mevaseret Yerushalayim, which is, indeed, connected to Jerusalem by the eruv, but is its own municipality. According to the second opinion stated above, its residents certainly must read the Megilla on the fourteenth, and some actually do so. According to the first opinion, however, they should read it on the fifteenth, because from some parts of Mevaseret, one can see the outskirts of expanded Jerusalem. In addition, its residents are dependent on Jerusalem to a degree, and, as already mentioned, the two cities are joined by an eruv. R. Messas ruled in accordance with this opinion, and R. Uri Cohen, head of the Meretz Kollel there, implemented this ruling in practice. See Oraĥ Mishpat §146, which states similarly regarding Bayit Vegan in 1920. (Bayit Vegan in those days was like Mevaseret Yerushalayim today.)
From 1948 to 1967, the Old City of Jerusalem was under Jordanian occupation. Because of this, the question arose: Should those residing in neighborhoods adjacent to the Old City celebrate Purim on the fifteenth, even though the area within the walls itself is bereft of Jews? Masat Moshe 2:3 and Birkei Yosef state that in such a situation, the Megilla is read on the fourteenth. The Vilna Gaon maintains, based on the Yerushalmi, that it is read on the fifteenth. Rashba and Ritva concur, and this was the practice in Jerusalem in those days. The proponents of this viewpoint suggest another rationale: Ancient Jerusalem was larger than the area known today as the Old City. R. Zvi Pesaĥ Frank accepted this in practice, recording his ruling in both Har Tzvi 2:131 and Mikra’ei Kodesh §25. It is worth adding that the whole reason Jews came to the new side of Jerusalem was in order to draw closer to the holy ancient Jerusalem. For this reason, all neighborhoods of Jerusalem are subordinate to it in all matters.