Sumatra Island is an Indonesian island located in the Indian Ocean. It is the sixth largest island in the world and is home to the provinces of North Sumatra, West Sumatra, Riau, Jambi, South Sumatra, and Bangka Belitung Islands. The two crossword solutions for the term Sumatra Island are NIAS and JAVA. NIAS is an island off the west coast of Sumatra, while JAVA is an island located in the JAVA Sea, south of Sumatra.