One of the claims that is often posted in internet forums and talkbacks by disengagement cult members is that the Gaza strip is not part of the Land of Israel. Indeed, Gaza appears many times in scripture as a Philistine city, for instance:
"And when the five lords of the Philistines had seen it, they returned to Ekron the same day. And these are the golden emerods which the Philistines returned for a guilt-offering unto the LORD: for Ashdod one, for Gaza one, for Ashkelon one, for Gath one, for Ekron one;" (Samuel I 6:16-17)
However, a close look at the Bible shows that Gaza is certainly part of the Promissed Land:
"This is the inheritance of the tribe of the children of Judah according to their families....Ashdod, its towns and its villages; Gaza, its towns and its villages; unto the Brook of Egypt, the Great Sea being the border thereof."(Joshua 15:1, 15:47)
True, Gaza was occupied by Philistines for a certain period, and is occupied by Arabs today. This in no way diminishes from the fact that Gaza is part of Eretz Yisrael.
With regards to settlements in Northern Samaria, even the disengagement cult admit that they are part of Biblical Israel.