AHA! California really was an island

First, Americans should know that there are today three Californias: upper (Alta California, USA), lower (Baja California, Mexico), and BC Sur (Southern tip, Mexico).

All three were part of Mexico for the longest time, but the British, Spanish, German, and other European settler colonialists now calling themselves the "Americans" decided to annex Alta California for their new settler colonial project.

We wouldn't be the only island, as Madagascar is to Africa, and we still have other islands.

This came amid their ongoing genocide of the indigenous folk living there, the Native or American Indians, following centuries of Spanish colonialism, which was aided and abetted by the Vatican (the Catholic Church and its maniacal "Doctrine of Discovery") and the Spanish throne. Could it be that it was once an island?

Yes. Here's why. If one travels up the Gulf of California in Mexico to San Felipe, one can easily imagine continuing all the way up to the Salton Sea (near Los Angeles), USA. That lowland desert is full of the remains of higher sea levels of the ancient past.

Connect green parts, with Gulf lower right

But where would it end? Would Alta California, USA, really be a part of a Mexican island or, as today, just a peninsula? The answer, as shown above, is Lake Corcoran (flowing out to the Pacific through the Carquinez Strait) and its ancient remnant Tulare Lake, which existed up until 1930.

Now it's a well-watered deserted and the nation's breadbasket, fondly called California's Central Valley.

Cartographers knew California was a lake and depicted as such in many maps. That was the legend, the lore, and the reality for European explorers and travelers. Even today we have a phantom lake (Lake Manly) in one of the lowest and hottest places on earth -- Death Valley, Alta California. 

The "Island of California" (Spanish Isla de California)

There was a long-held global (mis)conception, dating from the 16th century, that the California region was not part of mainland North America (of which Mexico is a part)

Rather, it was known to be a large island separated from the continent by a strait now known to be the Gulf of California (part of the Pacific Ocean and not part of the Gulf of Mexico on the Atlantic side).

One of the most famous cartographic "errors" in history, it was propagated on many maps during the 17th and 18th centuries, despite contradictory evidence from various explorers [1].

The legend was initially infused with the idea that California was a terrestrial paradise, like the Garden of Eden or Atlantis.

This mapping error -- which may not have been an error at all -- was not a one-off event. From the mid-1500s to the late 1700s [2] great controversy surrounded the geography of California.

For instance, a Spanish map from 1548 depicts California as a peninsula [3], while a 1622 Dutch map depicts California as an island.

A 1626 Portuguese map depicts the land as a peninsula, while a 1630 British map depicts it as an island [4].

A French map from 1682 only shows the tip of the Baja Peninsula.

There are slightly over 1,000 maps in Stanford's Glen McLaughlin Collection of California as an island, the largest collection of such maps in the world [5].

History

Why would anyone think this island was an island?

The first known mention of the legend of the "Island of California" was in the 1510 romance novel Las sergas de Esplandián by Garci Rodríguez de Montalvo—the sequel to Montalvo's more famous tales of Amadís de Gaula, father of Esplandian. He describes the island in this passage:

"Know, that on the right hand of the Indies there is an island called California very close to the side of the Terrestrial Paradise; and it is peopled by black women, without any man among them, for they live in the manner of Amazons [6]."

It is thought that, because of the widespread popularity of Las sergas de Esplandián at the time of European exploration of California, that it is reasonable that the book inspired the naming of California [7].

The book's description is also thought to have prompted early explorers to misidentify the Baja California peninsula as the island in these legends [7]. More: Island of California (Wikipedia)