Originally, Koh Kood was just a village under Koh Mak Subdistrict in Laem Ngop District, Trat Province. Later in 1980, Koh Kood was upgraded to Koh Kood Subdistrict. Because Koh Kood is quite far and remote from the mainland—about 40 kilometers from Klong Yai District (Trat side)—it was very difficult for local residents to travel to the mainland for government business. Additionally, Koh Kood is closer to Cambodian territory (Koh Kong) than to the Thai mainland. The government therefore implemented policies for national security and public convenience by elevating Koh Kood and neighboring islands into Koh Kood Minor District according to a Ministry of Interior announcement. Later, on August 24, 2007, Koh Kood was upgraded from a minor district to Koh Kood District, as it remains today.

Koh Kood first appears in historical records during the reign of King Rama I in 1782, the same year Bangkok was established. Ong Chiang Sue (the ruler of Vietnam at the time) and his family fled from the army of King Quy Nhon (Tay Son) after Saigon was attacked, seeking refuge under King Rama I in Bangkok. Later in 1786 (Chula Sakarat 1148), Ong Chiang Sue planned to return to reclaim his country. However, because Siam was actively engaged in war with Burma, he was afraid of royal punishment if he asked for permission directly. Ong Chiang Sue decided to write a farewell letter and escaped with several other Vietnamese followers. After escaping, they discussed where to go and decided to stay at Koh Kood. At that time, Koh Kood had no established communities or villages; most residents on the island were Thais who had migrated from Mueang Patjantakirikhet (Koh Kong) after it fell under French colonial rule in 1904. Ong Chiang Sue stayed on Koh Kood for one year. The area where he stayed is now known as Klong Chao Waterfall, which is the origin of the name "Klong Chao Waterfall," a famous waterfall on Koh Kood. Records also note that the oldest community on Koh Kood is the Khlong Mad community.

Distances from Mueang Trat District to other districts are:

• Khao Saming District: 16 kilometers

• Laem Ngop District: 17 kilometers

• Bo Rai District: 59 kilometers

• Klong Yai District: 74 kilometers

• Koh Chang District: 27 kilometers

• Koh Kood District: 82 kilometers