2nd-century BC geographers

Hipparchus (; , ;  BC) was a Greek astronomer, geographer, and mathematician. He is considered the founder of trigonometry, but is most famous for his incidental discovery of the precession of the equinoxes. Hipparchus was born in Nicaea, Bithynia, and probably died on the island of Rhodes, Greece. He is known to have been a working astronomer between 162 and 127 BC.

Agatharchides or Agatharchus ( or , Agatharchos) of Cnidus was a Greek historian and geographer (flourished 2nd century BC).

Han dynasty scholar

ancient scholar and topographic commentator

Scymnus of Chios (; fl. c. 185 BC) was a Greek geographer. It was thought he was the author of the Periodos to Nicomedes, a work on geography written in Classical Greek. It is an account of the world (περιήγησις, periegesis) in 'comic' iambic trimeters which is dedicated to a King Nicomedes of Bithynia. This is either Nicomedes II Epiphanes who reigned from 149 BC for an unknown number of years or his son, Nicomedes III Euergetes.

Athenian historian (2nd century BCE)