Kōkai-dō (黃海道, Korean: 황해도), alternatively Kōkai Province, was a province of Korea under Japanese rule. Its capital was at Kaishū (now Haeju). The province consisted of what is now the Hwanghae Province of North Korea.

Number of people by nationality according to the 1936 census:

• Overall population: 1,639,250 people
  • Japanese: 20,582 people
  • Koreans: 1,614,738 people
  • Other: 3,970 people

• Hwanghae Province
• Provinces of Korea
• Governor-General of Chōsen
• Administrative divisions of Korea