List of unidentified decedents in the United States
An unidentified decedent, or UID, is a deceased person whose legal identity is unable to be determined by law enforcement. Although the majority of UIDs are identified soon after their bodies are recovered, it is not uncommon for bodies to remain unidentified for years or even decades. There are approximately 40,000 unidentified decedents in the United States at any given time.
A deceased body can be identified in several different ways. Most commonly, a relative of the deceased identifies the body by sight. However, if a body is heavily decomposed, skeletal, or unrecognizable due to severe facial trauma at the time of recovery, other methods must be used. Some other common modes of identification include fingerprints, dental records, chest x-rays, and as a last resort, comparing the deceased's DNA to the DNA sequence of a genetically close relative such as a parent or sibling. In some cases, circumstantial evidence can be used to formally identify a body; for example, if the deceased has a driver's license on their person, or is found deceased on their own property after going missing, those context clues can be used to make an identification. Since identification of a deceased individual is a legal matter, officials require a high degree of certainty in order to make a formal identification.