The need to travel from place to place stems from man’s deficiency: he cannot find his livelihood and meet his needs by remaining stationary. So he must roam and leave his place. But the idea of Shabbat is for every Jew to rest from his travails and worries, contemplate the inner perfection of creation, thank God for choosing Israel from all peoples and giving us His Torah, and delight in God and His goodness.

For this reason, the Sages ordained boundaries (teĥumin) within which one may walk on Shabbat, and beyond which one may not walk. One’s teĥum Shabbat (Shabbat boundary) is determined by his mekom shevita – the place where he is spending Shabbat (literally “stopping place”) – plus 2,000 amot in each direction (2,000 amot corresponds to 2,000 steps of an average person, approximately 912 m).^[1]

If one is spending Shabbat in a field (i.e., not in a city or town), his mekom shevita is defined as four amot squared. This is the amount of space one occupies when lying on the ground with his arms and legs outstretched.^[2] He may walk 2,000 amot beyond that in each direction. If he is spending Shabbat in a city or town, the entire settled area is considered one place, and he may travel 2,000 amot beyond the city limits (see section 8 below).

According to Rambam and Smag, teĥum Shabbat restrictions are based on Torah law, though the Torah prohibition forbids one to travel more than twelve mil (24,000 amot, which is 10944 m, almost eleven km) from his mekom shevita. This is based on the size of the Israelite camp in the wilderness, as the Torah states: “Let everyone remain where he is; let no man leave his place on the seventh day” (Shemot 16:29). However, according to Ramban, Rosh, Rashba, and most Rishonim, this verse does not refer to the laws of teĥum but rather to those of carrying in a reshut ha-rabim; all boundary restrictions (even beyond twelve mil) are rabbinic law.^[3]

The Sages ordained that if one must travel beyond the teĥum on Shabbat – in order to attend a wedding celebration or a Torah lecture – he may make an eruv teĥumin, which extends his teĥum in the necessary direction (as explained below in sections 12-14). One who leaves his teĥum forfeits it and must remain within his four amot (as explained below, section 11).

The Sages established that one’s mekom shevita on Shabbat is square, and thus his teĥum is square as well. This means that if he is spending Shabbat in a field, and his mekom shevita is thus four amot, the measurement is not made by drawing a circle around him with a diameter of four amot. Rather, to determine his mekom shevita we inscribe such a circle in a square with four-ama sides along the four cardinal directions, which adds space to his mekom shevita at the corners. Similarly, if one’s mekom shevita is in a city or town, even if the area is round, we inscribe it in a square or rectangle, adding space at the corners (m. Eruvin 53a).

Then 2,000 amot are measured in each direction. Once again we draw a square or rectangle, which once again grants him additional space in the corners.^[4]

This rule, that we square off the city, is derived from the Torah’s description of the area the Levites were given outside each of their cities:

You shall measure off two thousand amot outside the city wall all around. You shall measure off two thousand amot outside the town on the east side (lit. corner; same applies to the other directions), two thousand on the south side, two thousand on the west side, and two thousand on the north side, with the city in the center. (Bamidbar 35:5)

The most straightforward explanation for why we square the teĥum is that it is extremely difficult to measure and mark off a circular boundary. One would need to measure 2,000 amot from almost each and every point of the city’s perimeter. In contrast, when marking off a square boundary, only four measurements need to be made – one in each of the four cardinal directions. After that, a straight line can be drawn in each direction, and the result is the teĥum.

Additionally, this method reflects a spiritual reality. A circle represents the infinite, which has no beginning and no end. A person’s life is circular and cyclical. His actions, wishes, and thoughts repeat themselves cyclically. Even his limbs are circular and cylindrical. This makes it difficult for a person to realize his aspirations. The way to solve the problem is to take one’s “circular” infinite ideas, and give them a “square” finite framework that will help him put them into practice. This is the meaning of teĥum Shabbat, which is meant to provide a framework for absorbing the holiness and blessing of Shabbat. This is why each city belonging to the Levites, who are charged with revealing faith in this world, is surrounded by a square boundary.

Teĥum Shabbat is specific to every individual, based on his location. For example, let us say that the homes of two neighbors (who do not live in a city) are located 1,000 amot apart from each other. Each neighbor has his own teĥum Shabbat, part of which overlaps with his neighbor’s teĥum Shabbat, and part of which does not.

The laws of teĥumin apply to one’s animals and belongings, and to Jews as well as non-Jews (see n, 12 below). Therefore, if one carried his talit to the edge of his teĥum, and his friend wants to borrow it but has a different teĥum, the friend may not carry the talit beyond its owner’s teĥum (SA 397:3). If the talit is jointly owned, it may be carried only where their teĥumin overlap (ibid., 397:9).

For someone who is spending Shabbat in a city or town, whether its residents are Jewish or non-Jewish, the whole area that is built up contiguously is considered one place, and the 2,000 amot of the teĥum are measured from its perimeter. Even if there is space between the homes, as long as they are surrounded by a fence or an eruv, the entire enclosed area is considered one place, and the 2,000 amot are measured from its perimeter (as will be explained in section 8).

All this pertains to one who spends Shabbat in the city or within its squared-off area. However, one who spends Shabbat in a field near the city is limited to 2,000 amot in each direction, and if his 2,000 amot terminate inside a city, his teĥum ends right there, in the middle of the city. We do not consider the whole city his four amot.^[5]

The Sages established rules for measuring the teĥum Shabbat as precisely as possible. First, they declared: “Teĥum Shabbat may be measured only with a rope that is fifty amot long, no more or less” (Eruvin 57b). If a longer rope were used, its weight would make it hard to pull taut, and the resulting measurement would be too short. If a shorter rope were used, one might pull it too tight, and the resulting measurement would be too long. Second, they required those measuring to hold the rope at chest height. If the person holding one end of the rope were to hold it at head level, while the person at the other end were to hold it at foot level, the resulting measurement would be too short (SA 399:1-3). Third, they said that when measuring an area that contains a valley, one person should stand on either side of the valley, so that they can measure the distance in the air. When measuring an area that contains a hill, tall poles should be set up so that the rope stretches above the hill. If the valley or hill is more than fifty amot wide, thus making it impossible to use a fifty-ama rope, the area should be measured with a four-ama rope. The person standing above should hold the rope at foot level, and the person standing below should hold it at chest level. If the slope is so steep that it would be difficult to calculate the measurement this way, the measurement should be estimated. If the area contains a cliff, as long as the cliff is less than four amot wide, it is not taken into account at all (Eruvin 58a-b; SA 399:4-5).

The Sages added that for these measurements, we rely only on an expert who knows how to calculate distances properly. If two experts arrive at different measurements, we follow the measurement that results in a larger teĥum. Since the laws of teĥum are rabbinic, we follow the more lenient opinion (Eruvin 58b-59a; SA 399:7-9). If one happens to spend Shabbat in a place where teĥum Shabbat has not been calculated, and he needs to go somewhere for the sake of a mitzva, he may take 2,000 medium-sized strides, which is approximately 2,000 amot (Eruvin 42a; SA 397:2; MB ad loc. 5).

Today it is best to establish teĥum Shabbat using aerial maps or GPS devices, as these can measure distances with extreme precision. We should not insist on measuring in the way that the Sages established. After all, their whole purpose was to measure as precisely as possible, using the tools available to them, without terribly inconveniencing those charged with measuring. Now that we have methods of measuring that are both more precise and more convenient, we must take advantage of them.

As we have seen (section 2), we square a person’s mekom shevita to determine his teĥum. If he is in a field (i.e., not in a city or town), his mekom shevita is a square with four-ama sides; if he is in a city, we inscribe the city in a square. From this square we measure 2,000 amot in each direction.

Let us add now that when we square the city, we do so based on the four cardinal directions (SA 398:3).^[6] If the city already has corners that lend themselves to squaring in a way that does not follow the four cardinal directions, the squaring is done accordingly (SA 398:1).

Examples of squaring based on the four cardinal directions:

Examples in which it is agreed that the squaring does not follow the four cardinal directions:

When a city’s shape lends itself to squaring that does not correspond to the four cardinal directions, the poskim disagree how to square it. Some maintain that only when there is a compelling reason not to follow the four cardinal directions may one follow the layout of the city (SAH 398:3; Ĥayei Adam 76:14). However, most poskim maintain that if the shape of a city clearly lends itself to squaring in a certain way, we follow this squaring even though it does not correspond to the four cardinal directions (see n. 7). In cases of doubt, the local rabbinate or rabbinic authority should make the decision.

Examples of such intermediate cases in which a city’s shape clearly lends itself to squaring in a direction other than the four cardinal directions include cases where one side of the city is straight from one end of the city to the other (figure 1) and cases where the perimeter of the city contains a right angle (figure 2, in which case we follow the directions of the right angle and not the four cardinal directions).^[7]

It is important to note that if one is spending Shabbat outside a city and his mekom shevita is limited to four amot square, he may choose to square his mekom shevita in whatever direction he wishes, and this will also determine how his 2,000-ama teĥum is squared (see section 12 below).

As we have seen, by squaring the city, we add space in the corners to the teĥum. However, the Sages pointed out that sometimes we cannot draw straight lines to square the whole city, because the resulting square would include uninhabited areas that are too large to be considered subsumed by the city. Examples of this would be cities that are shaped like a bow or like an L. The operative principle is that if there are 4,000 amot between the two ends of the shape, that part of the city cannot be squared.

An L-shaped city:

A bow-shaped city:^[8]

As long as the houses in a city are contiguous, meaning that they are not farther away from one another than the size of a karpif (a large courtyard, approximately 32 m long), they are considered part of one area for the purpose of assessing the teĥum. If they are separated from one another by more space than that, they are not considered part of one area, and each house’s teĥum Shabbat is then calculated separately.^[9]

If the houses in a city are contiguous, then even if one house is out of alignment, as long as it is not more than 32 m from the next house, the teĥum’s square or rectangle expands to include the unaligned house. If there are additional houses after this one, the teĥum expands to include them as well; this can continue even if it means that the teĥum extends outside the city proper for a distance that would take days to walk. As long as each house is not separated from the next by more than 32 m, the teĥum extends to include them. However, if a house is more than 32 m away, it is not included within the rectangle.

If the distance between two adjacent neighborhoods is greater than the size of two large courtyards (i.e., over 64 m), then each neighborhood is considered a town in its own right. We square each on its own, and then 2,000 amot are measured in each direction from that square. In contrast, if the distance separating the two neighborhoods is 64 m or less, they are considered one area and we square them together. There must be at least fifty residents living in an area for a group of houses to be defined as a neighborhood (Eruvin 60a). Even if there are fewer than fifty people, as long as the area contains three courtyards, each of which joins two homes together, or six homes, each of which has a courtyard, the area is still considered a neighborhood (MB 398:38; Ĥazon Ish OĤ 110:19).

If an area is enclosed by a wall or an eruv, all its homes and neighborhoods are considered one area. This is true even when the wall or eruv is farther than a karpif’s length from the last house, and even if there is a large distance between the homes and neighborhoods.

When the squares or rectangles formed around two cities overlap, even when there is no joint eruv, the overlapping area connects the cities. We draw a new rectangle around the entire area to include both cities. The residents of both cities may then walk 2,000 amot beyond the joint rectangle.

However, if the distance separating the corners of the two rectangles is greater than 4,000 amot, as we have seen (section 7), we do not square the entire area. Rather, each city is assigned a standard teĥum of 2,000 amot beyond its rectangle in each direction.

If a highway within a city is more than 64 m wide and bisects the entire city, then the city is viewed as divided in two, and the teĥum Shabbat for residents of each of the two sections is calculated separately. This is also the case for a wide-open area such as a park or large garden. If it is more than 64 m wide and bisects the entire city, then the city is viewed as divided in two, and the teĥum Shabbat for each of the two sections is calculated separately.

At first glance, it would seem that the Ayalon Highway divides Tel Aviv into two cities. Nevertheless, since there is an eruv that encompasses all of Tel Aviv and the nearby cities, the eruv unites the different sections. Additionally, if a highway bisects a city but the rectangles drawn around each section overlap, then the overlapping area joins together the sections and we draw a new rectangle around the entire area, as explained above. Additionally, one could argue that since it is intended that all a city’s residents will make use of a highway, park, or large garden, they are considered part of the city and do not actually divide it.

Others disagree, maintaining that these factors – an eruv, usage by all city residents, and overlapping rectangles – cannot join together the two sections formed by a highway or park that bisects a city. The primary position is the lenient one. However, it is proper to be stringent and avoid walking more than twelve mil beyond the highway, since some say that traveling beyond twelve mil is forbidden by Torah law (see section 1 above).^[10]