Ko Chang is an amphoe in Trat province, Thailand. It is on the Gulf of Thailand's eastern seaboard, 300 km from Bangkok, near the border with Cambodia. The island Ko Chang occupies most of the district's land area, along with several smaller islands. With an area of 210 km2, Ko Chang is the third-largest island in Thailand by area, after Phuket and Ko Samui. The name Ko Chang means 'Elephant Island' and derives from its elephant-shaped headland.