Famous cartographic errors – mistakes on old antique maps and why they happened

Twenty Famous Cartographic Errors: When Mapmakers Got It Spectacularly Wrong

Some of the most fascinating and collectible old maps are those that feature infamous cartographic errors. Below, we highlight twenty remarkable examples that showcase some of the best-known mistakes in the history of mapmaking. These include California depicted as an island, the fictitious Mountains of Kong in West Africa, a vast inland sea in the American West, the hypothetical southern continent Terra Australis, the legendary city of El Dorado, and the mythical island of Atlantis. Other notable errors include the Niger River flowing in the wrong direction, the supposed Lake Chiamay as the source of Southeast Asia’s rivers, phantom islands in Lake Superior and the South Atlantic, the imaginary Lake Apalachy in the Carolinas, and incorrect identifications of the Nile’s source.

Many of these errors have compelling backstories—for example, the fabricated voyages of the non-existent Admiral Fonte, whose fictional discoveries were concocted by a London publisher and appeared on numerous reputable maps. In earlier centuries, mistakes often stemmed from inaccurate surveys, speculative geography, or misinterpretations of explorers’ reports. Features were sometimes plotted in the wrong locations, duplicated, or dramatically exaggerated in scale. Transient phenomena such as cloud banks or floating pumice were occasionally mistaken for solid land. In many cases, legendary or entirely invented places were accepted as fact and repeated across successive editions of maps.

Some errors were even intentional. During the Age of Discovery, explorers had every incentive to “discover” new islands—often naming them after wealthy patrons to help secure future funding. In modern times, publishers of London A–Z street atlases have allegedly included fictitious “trap streets” to detect copyright infringement. The drive to publish the most up-to-date maps sometimes led to anticipatory mapping—depicting planned developments or speculative changes that never actually came to pass.

Intriguingly, some mapping errors persisted well into the modern era. Sandy Island, located near New Caledonia and shown on maps for over a century, was finally “undiscovered” by an Australian survey vessel in 2012.

Click the links above or below to browse the maps in our collection. Some are rare and may no longer be available for purchase—but we’ve included them here for their historical and visual interest. Enjoy exploring these remarkable examples of geographical misunderstanding, mythmaking, and mapmaking ambition.

Featured examples:

The Mountains of Kong, and Mountains of the Moon
Map by Tallis/Rapkin, 1851
Marked on the map are the Mountains of Kong, and their extension  the Mountains of the Moon, both non-existent ranges charted on many 19th century English maps of Africa. The Mountains of Kong originated in a 1798 map by English cartographer James Rennell, and persisted for 90 years. The mountains were thought to begin in Guinea, then continue east to the also fictitious Central African Mountains of the Moon. French explorer Louis Gustave Binger established that the mountains were fictitious in his 1887-1889 expedition to chart the Niger River. Some might say this shouldn't have been hard to establish, as the Niger river flowed in a southerly diretion from a position to the north of the supposed location of the mountains and emptied into the Gulf of Guinea, to theie south.

California as an Island
Rossi/Sanson, 1677
Perhaps the most famous cartographic error in history, it was a long-held misconception that California was a large island separated from continental North America. First mentioned as an island in 1510, this was disproved by de Ulloa’s expedition in 1539 and many subsequent 16th century maps correctly showed Baja California as a peninsula. However, the depiction as an island was revived in the 17th century, possibly due to overinterpretation of the 1592 discovery of the Strait of Juan de Fuca.

The Two Taprobana Error
Sebastian Münster, 1572
Ancient European geographers were long confused about the identity and location of the island of Sri Lanka, then known as Taprobana. Mistakenly conflating Sri Lanka with Sumatra, they often placed Taprobana in either or both locations: one near India, the other in Southeast Asia. This led to centuries of geographic ambiguity. The 16th-century cartographer Sebastian Münster dealt with the confusion by including the island on two different maps—one for each region—in his Cosmographia.

Lake Apalachy in the Carolinas
Homann, c.1720
The map shows a large non-existent lake “Apalache Lacus” within the Carolinas. This error originated in 1606 when the Dutch cartographer Hondius mistakenly added it to his map of the America south east, an error copied by later cartographers. In 1669, the explorer John Lederer even claimed to have visited the lake, reporting the water to be “brackish”. He named it Lake Ushery, though it came to be known as Lake Apalachy. Lakes Moultrie & Marion, in a similar location, were created in the 1940’s.

Lake Chiamay in Southeast Asia
Mallet, 1683
Mallet's map shows the mythical Lake Chiamay, once believed to be the source of the 5 great river systems of Southeast Asia (the Dharla, the Irrawaddy, the Mekong, the Chao Phraya & the Bramaputra).

The Sea of the West & Admiral Fonte’s Discoveries
De Lisle, 1750
This landmark map includes several famous cartographic errors. The inland “Sea or Bay of the West” occupies a vast part of the American west, opening into the Pacific – likely a gross misinterpretation of de Fuca’s report of the Strait of Georgia. The “discoveries” of the fictitious Admiral Fonte along the Pacific North West Coast are marked, as is the southern coastline of a supposed large landmass east of Kamchatka, discovered by Delisle & Chirikov in 1741, in fact the Aleutian islands.

Terra Australis – The Great Southern Continent
Mallet, 1683
Terra Australis – shown on this map with a northern coastline running most of the distance between Perth, Western Australia and Cape Horn – was a hypothetical continent first posited in Antiquity which appeared on maps from the 15th to the 18th centuries. It was not based on any actual surveying, but rather based on the hypothesis that continents in the Northern Hemisphere must be balanced by a similar area of land in the Southern Hemisphere.

Frozen Sea at the heart of Antarctica
Buache, 1763
In contrast to the "Terra Australis" oversized continent of Antarctica theory, in an adventurous example of speculative cartography, Philippe Buache proposed that the icebergs observed in the southern ocean by explorers must have originated from a large frozen sea at the South Pole, sandwiched between two landmasses. His theories were published by the Royal Academy in Paris, and later republished as this map in the Gentleman's Magazine in London. The map also includes numerous other errors, including New Zealand attached to the southern continent, and Australia attached to New Guines.

The Circular Zambesi River
Weller, 1862
The map shows early colonial Africa, at at time when western explorers and cartographers were still struggling to comprehend the network of African rivers. The Zambesi river has not been fully charted; some parts appear to have been assumed, being indicated by a dotted line, which suggest that the course of the river was circular! Most of the Congo river is uncharted.

Terre de Quir – The Southern Land of Pedro de Quir
Mallet, 1683
Many early cartographers of the southern hemisphere believed that there was a great southern continent “Terra Australis”, thought to extend significantly further north than the actual landmass of Antarctica. One proponent of this theory was Spanish explorer Pedro Fernandez de Quir. His claim to have discovered this southern continent was recognised on some maps as “Terre de Quir” or similar, a landmass which this map suggests incorporates both the Solomon Islands and New Zealand.

Phantom Islands of Lake Superior
Bellin, 1745
Bellin's map of the Great Lakes includes two phantom islands in Lake Superior: Isles Phelipeaux and Pontchartrain. This “error” is thought to have been intentional; the islands were named in honour of Louis Phélypeaux, Comte de Pontchartrain, possibly to curry his favour, as he was a government minister influential in allocating funds for voyages of exploration.

Lake Tana as the Source of the Nile
James Bruce, 1804
The explorer James Bruce travelled to Lake Tana, in what is now Ethiopia, aiming to prove it as the true source of the Nile. This is, in fact, close to the source of the shorter Blue Nile. At the time, the longer White Nile remained largely unexplored, and its origins were poorly understood. The true primary source of the Nile—by length and volume—was not identified and confirmed until 1858, when John Hanning Speke reached Lake Victoria.

Phantom Jardine Islands & Frisland
Numerous old maps include "phantom" islands - these are purported islands which were shown on maps for a period of time, but were later found not to exist. They usually originated from the reports of early sailors exploring new regions, and are commonly the result of navigational errors, mistaken observations, atmospheric distortions, unverified misinformation, or deliberate fabrication - stemming perhaps from the desire of ship's captains to have their name - or perhaps that of the patron of their voyage - associated with a discovery. Some remained on maps for centuries before being "un-discovered". Even at the time of publication, cartographers sometimes indicated doubt as to their existence by referring to them as "supposed islands". This 1603 Bertius map features the phantom island of Frisland south west of Iceland. "Los Jardines" are marked in two places on this 1830 Thomson map - though they exist in neither. They were not finally expunged from all charts until 1973. See numerous other examples here.

The Niger River Flowing West
Mallet, 1683
Western explorers and cartographers struggled for centuries to make sense of Africa’s complex river systems. Unable to reconcile the Niger River’s observed flow (west to east) with the assumed geography—particularly the imposing (and fictitious) Mountains of Kong—some 18th-century mapmakers often concluded, erroneously, that the Niger must rise near Lake Chad and flow westward into the Atlantic at Cape Verde. This confusion was likely compounded by its mistaken conflation with the Senegal River. In reality, the Niger originates in the Guinea Highlands of southeastern Guinea and flows in a great crescent: east through Mali and Niger, skirting the border with Benin, then turning south through Nigeria, where it ultimately discharges into the Gulf of Guinea.

The mythical lost city of El Dorado
SDUK, 1844
The legend of the mythical lost city of Eldorado, abudant with gold and sought since the advent of the Spanish Conquistadores, underwent several transformations through the centuries. Even as late as the mid-19th century, this map speculates on its whereabouts, indicating “a knot of low mountains here according to Humboldt, called Sierra Tunuhy supposed to abound in mineral riches, El Dorado?”. Humboldt had disproved its location next to the equally mythical Lake Parime in 1799-1803.

The "lost" continent of Atlantis in the Atlantic
William Scott-Elliot, 1925
So wildly wrong that we include this in our category of "Fantasy maps", although unlike other maps in that category, the cartographer apparently believed his map to be an accurate representation. This map shows the supposed lost continent or island of Atlantis to illustrate the scriptures or theories of the theosophists, a quasi-religion established in New York City in 1875

New Guinea Joined to Australia – No Torres Strait
Mallet, 1683
Although this early map by Alain Mallet is somewhat ambiguous, it omits the Torres Strait and suggests that New Guinea is physically joined to Cape York, northern Queensland

Admiral de Fonte’s “Discoveries” in the North Pacific
De Lisle, 1752
This map includes a number of famous cartographic errors, including the supposed “discoveries” in the North Pacific Ocean of the fictitious Admiral Fonte (whose expeditions, invented by a London-based publisher, were accepted as fact by a credulous audience wanting evidence of a north west passage). Also shown are the "Mer de l'Ouest" a non-existent inland sea occupying a vast part of the American west, and a supposed landmass east of Kamchatka “discovered” by Delisle/Chirikov in 1741 – in fact the Aleutian islands

Krakatoa before the Eruption
Indonesia, 1885
Cartography rendered wildly erroneous by the forces of nature, rather than a cartographer's error, this map shows Krakatoa before its cataclysmic 1883 eruption. Here it is after the eruption.

Oxhey, Hertfordshire: Suburb That Never Was
Geographia, 1937
The desire to publish the most-up-to-date maps, and to ensure that newly published maps are not quickly rendered obsolete, can cause publishers to prematurely include planned development. This map shows a planned suburban layout south of Watford, England in 1937, however much of this was never constructed, and the area subsequently built upon was developed with a different street layout from that shown.