The "Island of California" is shown on a 1650 map by Nicolas Sanson

The Island of California refers to a long-held European misconception, dating from the 16th century, that California was not part of mainland North America but rather a large island separated from the continent by the Mare Californica. One of the most famous cartographic errors in history, it predated European exploration of western North America and was propagated on many maps during that era, persisting for over two centuries despite contradictory evidence from later explorers. Such legends were usually infused with the idea that California was a terrestrial paradise, such as the Garden of Eden, in much the same as manner as legends surrounding Atlantis.

The first known mention of the legend of the "Island of California" was in the 1510 romance novel Las Sergas de Esplandián by Garcia Ordoñez de Montalvo, who described the island in the 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.

It is probable that this description by Montalvo prompted early explorers to misidentify Baja California as the island in these legends.

In 1539, Hernán Cortés, prompted in part by the description by Montalvo, sent the navigator Francisco de Ulloa northward along the coast of North America in search of the island. Ulloa's expedition, as well the expedition of Hernando de Alarcón the following year, proved that Baja California was a peninsula, not an island, and maps published in Europe, including the subsequent maps by Gerard Mercator and Abraham Ortelius, correctly showed California as a peninsula.

Despite the early conclusive evidence, however, the island depiction on maps gained favor in the late 16th century. In 1592, the navigator Juan de la Fuca, after exploring the Gulf of California, reported the existence of large opening on the coast of North America that possibly connected to Atlantic Ocean, providing the route for the Northwest Passage. In 1602, Sebastian Vizcaino navigated the California coast with Father Antonio de la Ascension, who wrote a journal of the voyage describing California as separated from the mainland.

The first appearance of the Island of California on a map dates to 1622 in a map by Henry Briggs that became the standard for many later maps throughout the 17th century.

In 1705, the Jesuit missionary Father Eusebio Francisco Kino proved that Baja California was a peninsula by walking from New Mexico to the entire Pacific coast of California. Subsequent maps in France began to display California correctly as a part of the mainland, but mapmakers in Netherlands, Germany, and England continued to propagate the error until the mid 1700s. In 1747 Ferdinand VII of Spain issued a formal decree that California was a part of the mainland.

See also: History of California

External links

• California as an Island (http://www.prigsbee.com/maps/calif.html)
• Philadelphia Print Shop Ltd. (http://www.philaprintshop.com/calis.html) Maps of California as an island