For over two centuries, the most authoritative maps of the world contained a massive geographical error. If a navigator looked at a chart created in London, Paris, or Madrid between the early 1600s and the late 1700s, they would see North America separated from the Pacific coast by a wide channel of water.
California was depicted not as the western edge of a continent, but as a massive island completely detached from the mainland. This mistake persisted in the face of contradictory evidence and influenced explorers, kings, and missionaries for generations.
A Myth Born from Fiction
The name “California” did not originate from an indigenous term or an explorer’s log. It came from a 1510 romance novel by Garci Rodríguez de Montalvo titled Las sergas de Esplandián. The author described an island rich in gold, populated entirely by women, and ruled by Queen Calafia. When Spanish expeditions reached the Baja peninsula in 1533, the rugged terrain appeared to match the description from the book.
Fortun Ximénez, a mutineer who landed there first, assumed he had found the mythical land. Hernán Cortés followed and established a short-lived colony. The initial discovery was of the southern tip of the peninsula, which further cemented the assumption that water surrounded the entire landmass.
The Error Spreads
Early explorers like Francisco de Ulloa actually sailed up the Gulf of California in 1539 and found the mouth of the Colorado River, which suggested a peninsula connection. However, this data failed to stop the error from taking root. In 1620, a Carmelite friar named Antonio de la Ascensión wrote a widely circulated account that described California as a separate landmass separated by the “Mediterranean Sea of California.”
Cartographers in Europe accepted this account over previous data. For the next hundred years, standard maps showed a channel of water running from the Gulf of California all the way north to the Strait of Juan de Fuca.
Walking Across the Sea
The correction required a man to walk where the maps showed an ocean. Eusebio Kino, a Jesuit missionary and cartographer, arrived in the region to establish missions. Between 1698 and 1701, he traveled extensively throughout the area.
During his travels, he reached the delta of the Colorado River. He stood on dry land and looked across to the other side. He realized that no water separated the mainland from the Baja peninsula, which stretches approximately 775 miles (1,247 kilometers). Kino published a map in 1705 titled “Passage by Land to California” to present his findings.
A Royal Decree of Reality
Even with Kino’s proof, the idea of the island remained popular among European mapmakers. It took nearly another half-century for the political authorities to intervene. In 1747, King Ferdinand VI of Spain issued a royal decree.
The proclamation officially stated that “California is not an Island.” This legal order forced cartographers to update their plates. By the time the path was corrected on paper, the island of California had existed on maps for longer than many actual empires.
For two centuries, the world's best maps contained a massive lie.
Charts made between 1620 and 1750 showed California as a giant island, separated from North America by a wide sea.
This geographical error fooled kings, explorers, and navigators for generations…🧵👇 pic.twitter.com/NiWBIeIVkB
— Fascinating True Stories (@FascinatingTrue) December 4, 2025