Isthmus is a narrow strip of land that connects two larger land areas. In the Americas, one main area that is an isthmus is Central America. Central America is the isthmus that connects North America to South America. It consists of seven countries: Belize, Guatemala, Honduras, El Salvador, Nicaragua, Costa Rica, and Panama. Panama, specifically, is known for the Panama Canal, a crucial waterway that connects the Pacific Ocean to the Atlantic Ocean, making it an important trade route. Therefore, when referring to an isthmus in the Americas, Central America is the main area to consider.