Numbers 23:9—God's vision of Israel as spoken by the mouth of Balaam—sets us on the right path to finding Joseph's walls, the bounds of his habitations. God describes Israel as "a people dwelling alone, not reckoning itself among the nations." Clearly, God does not envision Israel integrated into the world. Rather, He has always wanted Israel to be separated from it. This vision has a number of applications, one certainly pertaining to the moral sanctification God intends Israel to display in the Millennium. God's vision for Israel is a people distinct from all others—His people, not partaking of the curses of this world's international intrigues, imbroglios, poverty, disease, etc. As we know, those days are yet to come.
Relevant to national Israel today, however, the passage likely has geographic significance. God fulfilled His vision of an isolated Israel by situating some Israelites in England, Ireland, Australia, and New Zealand—on islands. (Australia is a continent-sized island.) He located America and Canada in the New World, effectively isolating them from other major nations by vast oceans. By doing so, God insulated Israel from the world.
In other scriptures, God is more specific about modern-day Israel's boundaries. When he addresses Israel in prophecies that have clear, latter-day application, He refers to Israel as residing at the coasts (or coastlands) and in the isles. Additionally, Israel dwells in the north and west. Taking Jerusalem as the geographic starting point, Israel will reside to the north and west of the Middle East in the time of the end. Here are a few passages.
» Hosea 11:10: In context, God is prophesying about Ephraim's return—from the west—to his inheritance. (Often God uses Ephraim as an emblem for all Israel, much as the word Washington often refers to the United States as a whole.)
» Isaiah 49:1, 8-13: Again, God is describing His re-gathering of Israel. The "coastlands" and "people from afar" (verse 1) may refer to the lands of Israelites living in the southern hemisphere (see also Isaiah 41:1). Others will return "from the north and the west" (verse 12).
» Jeremiah 3:12: God tells Jeremiah to "Go and proclaim these words toward the north and say,
'Return, backsliding Israel. . . .'" This cannot refer to the ancient Kingdom of Israel, north of Judah, for it was already in captivity long before Jeremiah's day. God is telling Jeremiah to go further north and warn His apostate people.
» Jeremiah 31:7-10: God promises He will save His people residing in the north (verse 8). Those of His people in the "isles afar off" (verse 10) are probably those of New Zealand and Australia.
Joseph runs "over the wall" when he attempts to extend his influence beyond the isolated lands God gave him. This extension of influence can be cultural, economic, and even military. From a modern policy perspective, America stays within her walls as long as she follows a national policy of isolationism—remaining isolated from foreign nations as much as possible. When America follows a course of internationalism—the doctrine that it is proper to intervene (passively or even militarily) in other nations' affairs—she usually starts to overclimb the walls God established for her.
It is fair to see American history as a slow march from isolationism to internationalism. That is, America started out isolated, purposefully distinct from other nations. Ever so slowly, though, she began to take an internationalist stance, overclimbing the wall, until she finally became deeply entangled in the military and economic affairs of the world's nations.