For a while, people thought California was an island. Then they didn't. Then they did again. Then they didn't.

The name California came from Garci Rodríguez de Montalvo and his 1510 romance novel, "Las sergas de Esplandián".

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.

The Spanish ran into Baja California in 1533, and by sailing and walking around they figured out it was a peninsula in 1539 (thanks to Cortes, and Ulloa, who found the mouth of the Colorado river). This world map was published in Spain in 1552 and got it (and most of the world) pretty much right! Good work, Francisco López de Gómara the cartographer!

https://searchworks.stanford.edu/view/zw996zy2690

1606: California get labeled, and it's a peninsula.

https://searchworks.stanford.edu/view/nm595xv6478

But the Spanish started second guessing themselves in the early 1600s. Either that, or what seems most likely is that the Spanish wanted California to be an island, because it meant that any claims by the English to "New Albion" via Sir Francis Drake, who cruised by California in 1579 (yet completely missed San Francisco Bay thanks to Karl the Fog), were invalid.

When Juan de Oñate, the Spanish governor of New Mexico came down the Colorado River in 1605, he and his friends "thought they saw" the Gulf of Mexico continuing up to the northwest. Also, garbled stories of Juan de Fuca and the straight he discovered in 1592 (aka Vancouver Island) may given people the idea of a northern passage. And the myth thanks to that romance novel was strong.

Anyway, here's the first known map of California as an island in 1622, published in Holland.

https://searchworks.stanford.edu/view/hf530hv9225

Maps were often state secrets, and it seems that the Dutch stole copied old Spanish maps and the British stole copied those, and insisted it was an island until the 1700s.

This map published in London in 1625 is the first known map in English with California as an island.

It has a pretty awesome inscription.

https://searchworks.stanford.edu/view/9917574

This implies there were secret Spanish maps with California as an island floating around (like, literally, taken from captured ships) which does makes you wonder if this was all a giant disinformation game being played by Spain to invalidate Sir Francis Drake.

Signs that this got out of hand include Antonio de Herrera y Tordesillas, a Spanish historian. He published a history of Americas in 1601 with this map of California as a peninsula...

...but then included a map of California as an island in a reprint of his book in 1622, via Colijn.

https://searchworks.stanford.edu/view/hf530hv9225

Here's a Dutch map published by Vinckeboons in 1672:

And a British map from 1700 by Herman Moll:

Moll once said, "Of course California is an Island. I have had in this office mariners who have sailed round it."

More here: https://www.geographicus.com/P/AntiqueMap/NorthAmerica-moll-1701

So when did Europeans figure out California was not an island? It looks like some folks had their doubts in the late 17th century. While these Venetian maps from 1680 and 1697 shows California as an island, they have a cartouche describing the debate. I don't speak Italian, but Ulloa and 1539 and Cabrillo are mentioned.

https://searchworks.stanford.edu/view/9803004 https://searchworks.stanford.edu/view/zm373fj7922

Bonus: That map is part of a gore, those curved strips you can cut out and make into a globe. There are a couple of those in the collection and they are highly theraputic to print and cut out.

https://searchworks.stanford.edu/?f%5Bcollection%5D%5B%5D=zb871zd0767&q=gore&utf8=%E2%9C%93

Eusabio Kino, a Jesuit missionary, who even drew a map of California was an island, but by sailing and walking around he figured out that it was not an island but a peninsula and by 1701 made another map.

https://searchworks.stanford.edu/view/9949302

Moll never seems to have published a map of California as a peninsula, but you can see some creative map layout by 1711 that avoided showing the top of the island, and adding the "Gulf of California".

California started appearing as a peninsula on more maps after Kino. This French map from 1770 is great as it shows how California was depicted in other maps in 1604, 1656, 1700, 1705 and 1767 the years (basically a much more efficient version of this post).

There's an entire collection of California as an island maps over at the Stanford Library and a nice article about the collection in Business Insider.

Anyway I made a map of California as an island too.

I used Mapwarper to georectify that Dutch map published by Vinckeboons in 1672 to get the coast to line up, and took some liberties with masking the new coastline to the east of California. I added coastal features, along with what I assume are ports.

Sorry Nevada and Oregon.

Here's a link to a slippy map, have fun. It shows the "original" Isla California map place names at lower zoom levels thanks to tangram.js and some unnatural manipulation of GeoJSON and vector tiles. For fun I added the "modern" road network and "current" place names as you zoom in. The long bridges! Las Vegas! OMG

https://burritojustice.github.io/california-as-an-island/