The US borders to the north with Canada and to the south with Mexico. Right? Errrr, not quite.
Just as there are places along the US-Canada border where Canada is in the south (Detroit is north of Windsor, Ontario), there is also a small area where the US is south of Mexico. We can blame the Colorado river for this geographical oddity.
This river, famous for the massive canyon it forms, ends its course in the Gulf of California. For about 50km it serves as the border between the two North American countries.
600m where the North is South
Nature is fickle and does not allow rivers to flow in a perfect straight line. Oh no, they like to bend a little bit. It is in one of those bends (meandros, as known in Spanish), where it turns sharply into the northeast. Thus allowing a few Mexicans to sit on their porches to watch their “southern” neighbors work on the greenfields.
When I write ” a few Mexicans”, I really mean it. The bend where Mexico sits on top of the border is barely 600m long and there are only a couple of houses. The rest is agriculture area.
The river cuts through some of the driest areas of the Sonora desert. However, on its ending kilometers it becomes the source of water for a number of irrigation districts on both sides of the border. This allows for intensive agriculture in the middle of the desert. You can go from the massive Los Algodones sand dunes to greenfields by just crossing a highway.
The major urban areas close to this point are Mexicali and San Luis Rio Colorado (Mexican side), Yuma and El Centro (American side). Only Mexicali and Yuma have proper air services. If you ever think of visiting this place consider that El Pinacate Biosphere Reserve is very close and offers great dramatic landscapes mountains, desert, plenty of desert fauna and… sunken craters.
Is it the only place where Mexico is north?
Not really. In fact the low Rio Grande also forms a number of big bends. Many of them also bend so much that the USA soil is located south of Mexico. That is particularly common close to Nuevo Laredo (Tamps) / Laredo (Texas) and Reynosas (Tamps) / McAllen (Texas).
Rio Grande the long river dividing Mexico and the US is also called Río Bravo in Mexico. Same river, two names.