The Kaukonahua Stream or Kaukonahua River is a 9.9-mile-long (15.9 km) river on the island of Oʻahu which is one of the Hawaiian Islands. Including its longer South Fork, the stream's total length is 28.0 miles (45.1 km). It flows down in a generally northwest direction, from (21°30′7″N157°54′13″W) into the Pacific Ocean. The North and South forks meet at coordinates (21°29′44″N158°5′50″W) It is the longest river of the whole island group.