3rd-century BC geographers

Eratosthenes of Cyrene ( ; ;  – ) was an Ancient Greek polymath: a philosopher, scholar, mathematician, geographer, poet, astronomer, and music theorist. Eratosthenes eventually became the chief librarian at the Library of Alexandria. His work was the precursor to the modern discipline of geography, and he introduced some of its terminology, coining the terms geography and geographer.

Pytheas of Massalia (; Ancient Greek: Πυθέας ὁ Μασσαλιώτης Pythéās ho Massaliōtēs; Latin: Pytheas Massiliensis; born 350 BC, 320–306 BC) was a Greek geographer, explorer and astronomer from the Greek colony of Massalia (modern-day Marseille, France). He made a voyage of exploration to Northern Europe in about 325 BC, but his account of it, known widely in antiquity, has not survived and is now known only through the writings of others.

Megasthenes ( ; , died 290 BCE) was an ancient Greek historian, indologist, diplomat, ethnographer and explorer in the Hellenistic period. He described India in his book Indica, which is now lost, but has been partially reconstructed from literary fragments found in later authors that quoted his work. Megasthenes was the first person from the Western world to leave a written description of India.

ancient Greek mathematician

right|thumb|200px|Dicaearchus of Messana Dicaearchus of Messana (; Dikaiarkhos; ), also written Dikaiarchos (), was a Greek philosopher, geographer and author. Dicaearchus was a student of Aristotle in the Lyceum. Very little of his work remains extant. He wrote on geography and the history of Greece, of which his most important work was his Life of Greece. Although modern scholars often consider him a pioneer in the field of cartography, this is based on a misinterpretation of a reference in Cicero to Dicaearchus's tabulae, which does not refer to any maps made by Dicaearchus but is a pun on

Timosthenes of Rhodes (Greek: ) (fl. 270 BCE) was a Greek navigator, geographer and admiral in Ptolemaic navy. He is credited with inventing the system of twelve winds that became known as the Greek 12-wind rose.

Ancient Macedonian general and geographer

Demodamas () (flourished in the 3rd century BC), was a Seleucid official of the 3rd century BC. Demodamas was born in Miletus, and was the son of Aristides. He served as a general of the Seleucids under Seleucus I Nicator and Antiochus I Soter. Around 294–293 and 281–280 BC, Demodamas served as the satrap of the Seleucids in Bactria and Sogdiana. At the time, he undertook military expeditions across the Syr Darya to explore the lands of the Scythians, during which he traveled further to the north than any Greeks before him, with the possible exception of Alexander the Great. During the expedit

Deimachus or Daimachus (; ) was a Greek from Plataeae, who lived during the third-century BCE. He became an ambassador to the court of the Mauryan ruler Bindusara "Amitragatha" (son of Chandragupta Maurya) in Pataliputra in India. Deimachus was sent by Antiochus I Soter.