Cartimandua or Cartismandua (reigned c. AD 43 – c. 69) was a 1st-century queen of the Brigantes, a Celtic people living in what is now northern England. She came to power around the time of the Roman conquest of Britain, and formed a large tribal agglomeration that became loyal to Rome. The only account of her is by the Roman historian Tacitus, through which she appears to have been widely influential in early Roman Britain. Her name may be a compound of the Common Celtic roots *carti- "chase, expel, send" and *mandu- "pony".