The siege of Eupatoria (c.72-71 B.C.) was one of the shorter sieges during the Roman general Lucullus's invasion of Pontus (Third Mithridatic War). Eupatoria was a short-lived city. Mithridates VI Eupator founded it, at the junction of the rivers Iris and Lycus, but despite being a Royal foundation the city never minted coins. According to Memnon the city was destroyed by Lucullus after the siege. A few years later Pompey renamed it Magnopolis, but this name disappeared within a generation.
The date of the siege is uncertain. According to Appian Lucullus began the siege at the start of his campaign in Pontus (probably 72 B.C., but possibly the previous year), and before Mithridates was defeated at Cabira, further east up the Lycus River. Memnon places the end of the siege after the fighting at Cabira, but his account only survives in a summary provided by Photius in the ninth century, probably writing eight hundred years after Memnon. Photius's summary describes Lucullus as beginning to besiege Eupatoria, but that doesn't exclude the possibility that other Roman troops had been blockading the city before this.
The idea that the siege of Eupatoria began after the end of the campaign at Cabira is sometimes dismissed on the grounds that it might have posed a threat to Lucullus's supply lines, but the accounts of that fighting make it clear that Lucullus was getting his supplies from Cappadocia, to the south, and not from the west, so it is possible that Eupatoria was left alone until Mithridates had been defeated. Mithridates is also said to have sent supplies to Amisus, on the coast, while based at Cabira, which might imply that he had control of the rivers.
Memnon gives the best account of the end of the siege. After defeating Mithridates at Amisus, Lucullus went to Amisus and attempted to convince the defenders of that city to come over to the Romans. When they refused he moved against Eupatoria, where he pretended to conduct the siege negligently. Once the defenders were lulled into a false sense of security Lucullus ordered his men to assault the walls, using assault ladders. The attack was a success, and according to Memnon the city was then destroyed.