Identification for one of the missing tourists was discovered near the area where the bones were found.
Authorities are now trying to identify the remains and determine a cause of death.
The tourists, including two boys ages 4 and 10, went missing in Death Valley in the summer of 1996, when daytime temperatures reached 120 degrees.
Several months later, their minivan was spotted in a ravine but the victims were never found.
AP contributed to this report.