Though lots of countries are mentioned—Tyre, Lebanon, Sheba, etc.—in 1st Kings, the action takes place in good ol' Israel, God's promised land. David spent much of his life fighting to secure the territory that Solomon inherits, but pretty soon the kingdom is divided and neighboring nations start trying to chip away at Israel's borders.
This represents one of Solomon's greatest failures, since the land of Israel is a huge part of the covenant God made with Abraham when the people of Israel didn't even exist yet. He swore to Abraham that his posterity would live in Canaan (which is where Israel is) in peace and prosperity as long as they were righteous. The fact that they're losing land during 1st Kings is evidence that they're not holding up their end of the bargain.