R. Nachman Bar Yitzchak says that everyone agrees that if a Get is brought in a boat in the rivers of Eretz Yisrael it is the same as bringing it on dry land. (1)
If a Get is brought in a boat in the Yam ha'Gadol it is a Machlokes Tana'im whether it is regarded as Eretz Yisrael. (2)
The slope of Har Amnon towards south is Eretz Yisrael and towards north is Chutz la'Aretz.
The islands in the Yam ha'Gadol that are the further east than the western most land of Eretz Yisrael are part of Eretz Yisrael. (4)
Rebbi Yehudah says that all of the Yam ha'Gadol which is directly opposite the borders of Eretz Yisrael is part of Eretz Yisrael. (5)
Someone who sells his servant to a buyer in Ako or in Suriyah the servant goes free. (6)
The earth of Suriyah is Tamei just like Chutz la'Aretz and a Shali'ach who brings a Get from Suriyah must say B'Fanai Nichtav.
The Dinim of Ma'aser and Shevi'is apply to produce that grows in Suriyah according to the Tana who holds that Kibush (annexation) by a Yachid is a Kibush.
If someone enters Chutz la'Aretz in a chest according to Rebbi he is Tamei from the earth of Eretz ha'Amim, but Rebbi Yosi Bar Yehudah holds that he is Tahor.
Even according to Rebbi if someone enters Suriyah in a chest he is Tahor from the Tum'ah of Eretz ha'Amim. (7)
If someone buys a field in Suriyah from a Nochri he can have a Shtar written by a Nochri even on Shabbos. (8)
If a servant brings his Shtar Shichrur from Medinas ha'Yam and it states that you are Koneh yourself and my property, he is only Koneh himself but not the property. (9)
A BIT MORE
1. And it is not necessary for the Shali'ach to say B'Fanai Nichtav.
2. According to Rebbi Yehudah it is regarded as Eretz Yisrael and it is not necessary for the Shali'ach to say B'Fanai Nichtav and the Chachamim hold that the Yam ha'Gadol is outside the borders of Eretz Yisrael.
3. Har Amnon is Har ha'Har which is the northwest border of Eretz Yisrael. The top of the mountain is the border.
4. A line is drawn from the northwest corner of Eretz Yisrael to the southwest corner and whichever part of the island is within the line is regarded as part of Eretz Yisrael.
5. Even if they are a great distance from Eretz Yisrael. A line is drawn from the northwest corner of Eretz Yisrael toward the Atlantic and from the southwest corner toward the Atlantic and whichever part of the islands are within the lines are regarded as part of Eretz Yisrael.
6. The Chachamim decreed that someone who sells his servant to a buyer in Chutz la'Aretz the servant goes free and Ako and Suriyah are regarded as Chutz la'Aretz for this Din.
7. In Suriyah only the earth is Tamei but not the air while in the rest of Chutz la'Aretz both the earth and the air is Tamei.
8. Even though doing Melachah by means of a Nochri is a Shevus and is forbidden mid'Rabanan, for the purpose of Yishuv Eretz Yisrael it is permitted.
9. The same would be true if the Shtar stated that you are Koneh all my property. When a servant brings a Get he must say B'Fanai Nichtav, however he is only believed regarding his Shichrur not regarding the property. Therefore he only acquires the property if two witnesses authenticate the signatures on the Shtar.
TUM'AS ERETZ HA'AMIM
In Suriyah only the earth is Tamei but not the air while in the rest of Chutz la'Aretz both the earth and the air is Tamei. Why does the Tum'ah of the earth apply to Suriyah but not the Tum'ah of the air? The Pnei Yehoshua answers that the Tum'ah of the earth and of the air are two separate decrees for different reasons. The Chachamim decreed that the earth of Eretz ha'Amim is Tamei with Tum'as ha'Mes because of the Mesim of the Mabul and the Mesim that were killed by Nevuchadnetzar. The Mabul did not come down in Eretz Yisrael but it did come down in Suriyah and the Mesim of Nevuchadnetzar were removed from Eretz Yisrael but not from Suriyah. Therefore the decree of the Tum'ah of the earth applies to Suriyah. However, the decree of the Tum'ah of the air was to discourage us from leaving Eretz Yisrael and going to Chutz la'Aretz and this does not apply to Eretz Yisrael since our Tana holds that Suriyah has a Din of Eretz Yisrael.
The rivers in Eretz Yisrael and the islands in the Yam ha'Gadol within the Techum of Eretz Yisrael have a Din of Eretz Yisrael. The islands outside of Techum of Eretz Yisrael have the Din of Chutz la'Aretz. Bavel has a Din of Eretz Yisrael with respect to Gitin. (Rambam Hilchos Gerushin 7:10)