I've always imagined that Berit Ben Habetarim was done in Eretz Yisrael, but someone recently told me it happened in Haran.
Anybody have any sources for either?
The question is a matter of Machlokes in Rishonim on the relevant Pesukim.
I believe the Ibn Ezra takes the position that the Bris Bein HaBesarim is dated 430 years before the Jews left Mitzrayim. According to that, Avraham's first revelation was while in Charan. (If the 400 years of the Bris Bein HaBesarim is counted from Yitzchak's birth, then he only left Charan 25 years earlier, placing him there at 430 years before).
Other opinions put the Bris Bein HaBesarim around the events where it is described - after the war where his nephew Lot was captured, which would make it in Eretz Yisroel, and the 430 years counts from when he left Ur Kasdim five years before he left Charan, as that was the true beginning of the journey that culminated in the Exodus from Mitzrayim.
This in turn turns on where he was born. Ibn Ezra holds Charan (thus it is his birth place that he leaves in the beginning of Lech Lecha) - his family moved to Ur Kasdim and then back again. Thus leaving Ur Kasdim isn't a significant enough event to create the 430 year mark.
What Rashi holds in this is a long discussion - on the one hand he says Charan was not the birth place - rather the "birth place" is continue traveling from Charan like you traveled from your birth place - on the other hand, he says that the "decree" of the Bris Bein HaBesarim is where the 430 years start. If I ever have the time, I have a long convoluted question to ask about it - if I ever get to untangling it I will ask here.
There is a spot on a mountain slope in the Western Golan region of Israel, right next to the border with Lebanon.
The Kabbalists of Tzfat used to make a pilgrimmage to Mount Betarim, some time around Parshat Lech Lecha. They seem to accept as authentic a Muslim tradition that this is the correct spot.
Today, there is an organized group that ventures to Mount Betarim once a year, on the Friday before Parshat Lech Lecha. Unfortunately, because the site is right next to the border with Lebanon, individuals cannot make this hike alone. Only pre-arranged groups are allowed, and IDF soldiers accompany the group at all times.
There is a shelter of sorts which marks the spot , and the hikers go up there with a Torah scroll, and read the passage of the Covenant Between the Parts (without a bracha or aliyot l'torah). Source for this last point: my own eyes and ears. I did the hike several years ago.