This is not very well-known, but the actual southern boundary of North America is the Atrato and Cupica Rivers in Colombia. This means that a little piece of Choco Province in Colombia is actually part of North America. The Colombian government once had plans to build a canal in this area; but they realized that whatever they built would become the defacto boundary between the two continents. Fearing Panamanian territorial aggrandizement, the Colombians decided not to build it after all. I guess they saw what happened with that other continental border, the Suez Canal, during the Arab-Israeli Wars. Now that Mubarak is overthrown, there soon may be another bout of fighting on that troubled canal.
There are several possible answers to this question depending on what perspective you are asking the question from.
1. The coast line, generally excluding islands, for land-based travel purposes
2. The edge of the continental shelf for legal/governmental mineral leasing related purposes
3. 250 nautical miles East from any given point along the coast line or island owned by one of the countries, whichever is farther East, for shipping related legal purposes (recognized by both Canada and US under international treaty -
Pacific, Atlantic and Arctic Oceans, and the southern border of Mexico.
Strangely, British people consider North America to include the Central American region and the Caribbean as well, meaning it runs all the way down to the top of South America.
the atlantic
Two
Waterways can be hard to get across so surrounding or going around it would be a natrual boundary. Countries and states on North America are mostly separated by artificial boundaries. The artificial boundaries are called boarders. All of North America is surrounded by water. The water is a natural boundary of the entire continent.
The City of Chicago is located within the boundaries of Cook and DuPage Counties which are located within the boundaries of the State of Illinois which is located within the boundaries of the United States of America which is located within the boundaries of the continent of North America.
North America and South America have edges that are not all plate boundaries. The boundary between North and South America is known as the Central American Subduction Zone, where the Cocos Plate is subducting beneath the Caribbean Plate.
North America is large enough for the US to fit within its boundaries.
The Mississippi and the Missouri rivers are on the continent of North America.
The largest desert in North America is the Great Basin Desert followed closely by the Chihuahuan Desert. It depends upon where the 'experts' draw the boundaries.
The San Andreas Fault zone of western North America.
The North Pacific Ocean is to the West of North America. The boundaries are: North-Artic Ocean South-Southern Ocean West-Americas East-Australia and Asia
oregon
There are a number of natural boundaries of North Korea. These boundaries include the Korean Bay to the west, the Sea of Japan to the east, and the Duman River to the north.