Piri Reis (full name Hadji Muhiddin Piri Ibn Hadji Mehmed, reis/rais is Turkish and Arabic for captain) (about 1465–1554 or 1555) is an Ottoman-Turkish Kaptan-ı Derya, geographer and cartographer born between 1465 and 1470 in Gallipoli on the Aegean coast of Turkey.

He is primarily known today for his maps and charts collected in his Kitab-ı Bahriye (Book of Navigation), a book which contains detailed information on navigation as well as extremely accurate charts describing the important ports and cities of the Mediterranean Sea.

He gained fame as a cartographer when a small part of his first world map (prepared in 1513) was discovered in 1929 at Topkapı Palace in Istanbul.

The most surprising aspect was the presence of the Americas on an Ottoman map, making it the oldest known Turkish map showing the New World, and one of the oldest maps of America still in existence in the world.

(The oldest known map of America that is still in existence is the map drawn by Juan de la Cosa in 1500, which is conserved in the Naval Museum (Museo Naval) of Madrid, Spain.)

The most striking characteristic of the first world map (1513) of Piri Reis, however, is the level of accuracy in positioning the continents (particularly the relation between Africa and South America) which was unparalleled for its time.

Even maps drawn decades later did not have such accurate positioning and proportions; a quality which can be observed in other maps of Piri Reis in his Kitab-ı Bahriye (Book of Navigation).

Piri Reis' map is centered in the Sahara at the Tropic of Cancer latitude.

Charles Hapgood argued in Maps of the Ancient Sea-Kings that the Piri Reis map preserved knowledge of Antarctica from an Ice Age civilization.

In 1528, Piri Reis draws a second world map, of which a small fragment showing Greenland and North America from Labrador and Newfoundland in the north to Florida, Cuba and parts of Central America in the south still survives.