Year 171 BC was a year of the pre-Julian Roman calendar. At the time it was known as the Year of the Consulship of Crassus and Longinus (or, less frequently, year 583 Ab urbe condita). The denomination 171 BC for this year has been used since the early medieval period, when the Anno Dominicalendar era became the prevalent method in Europe for naming years.
Events
By place
Greece
Epirus joins Macedonia in the latter's fight against Rome. However, the Greek leagues remain neutral.
The first Roman colony outside Italy is founded at Carteia in southern Hispania after Iberian-born descendants of Roman soldiers appear before the Roman Senate to request a town to live in and are given Carteia, which is named Colonia Libertinorum Carteia.