Our Gemara offers two opinions with regard to this question. According to the hakhamim, the western border of Israel is a straight line drawn from Taurus Amanus – a mountain range in Syria – to Wadi El Arish in the Sinai. This includes the water off the Mediterranean coast, which includes a number of small islands. Rabbi Yehuda suggests that the western border extends much further, measuring the length of Israel from north to south and ranging westward to include the Mediterranean Sea until the Atlantic Ocean.
This discussion parallels the modern international law question of our day regarding territorial water rights. Every nation claims sovereignty – full or partial – over its neighboring seas and oceans, and with regard to certain claims this area may be viewed as an actual part of the country itself. There is no set law that regulates these claims, and some countries claim that the ocean three, twelve, or even 200 nautical miles off the coast belongs to them. With regard to certain economic rights – for example, fishing rights or the right to drill for oil – countries claim ownership over areas well into the sea. The argument between Rabbi Yehuda and the hakhamim is over the appropriate boundary line that should be drawn in the waters that neighbor the land of Israel.
The specific place names that are brought as the places where Israel’s boundaries begin and end are based on passages in the Torah (Bamidbar chapter 34 and Sefer Yehoshua). From a practical standpoint of halakha, however, the boundaries that are important to us are those of the Second Temple period. This area is significantly smaller than those discussed by Rabbi Yehuda and the hakhamim, particularly on the northern end.