The battle of Labraunda (497 BC) was the second of three battles between the Persians and Carian rebels during the Ionian Revolt, and was a second costly defeat for the Carians.
Caria had joined the Ionian revolt in the aftermath of the Ionian raid on Sardis (498 BC). Their revolt disrupted the first Persian counterattack of the war, led by three sons-in-law of Darius I. One of those armies, under Daurises, was sent to the Hellespont, where he was able to recapture Dardanus, Abydus, Percote, Lampsacus and Paesus without many problems.
When the news arrived of the Carian revolt Daurises abandoned his campaign in the Hellespont, and moved south towards Caria. The Carians held a conference at the White Pillars on the River Marsyas, and decided to make their stand on the south bank of the River Maeander, forcing the Persians to fight with their backs to the river. This plan backfired, and the battle of the Maeander turned into a major Persian victory.
According to Herodotus the Carians lost 10,000 men, and the survivors retreated south to the sanctuary of Zeus the God of War at Labraunda. This was west of the River Marsyas, and at the eastern end of the peninsular that led to the Ionian city of Miletus. The Carians were split into two factions, with one wanting to surrender to the Persians and other wanting to migrate from Asia Minor, but their morale recovered when reinforcements arrived from Miletus.
The combined Carian and Milesian army decided to stand and fight. The Persians advanced south from the Maeander, and attacked them. Herodotus doesn't say where this battle took place, but also doesn't mention any movement from the sanctuary, so Labraunda is a reasonable guess for its location.
This second battle also ended in a major Persian victory, again with heavy casualties amongst the Carians and Milesians. Herodotus reports that the losses at this battle were even heavier than at the Maeander.
This second defeat didn't end the struggle. After a pause of uncertain length the Persians prepared to move against the Carian cities, but they ran into an ambush at Pedasa (497 or 496 BC) and suffered a heavy defeat that effectively ended the first Persian counterattack.