The common law distinguished between lost property and mislaid property. Lost property is personal property that was unintentionally left by its true owner. Mislaid property is personal property that was intentionally set down by its owner and then forgotten. For example, a wallet that falls out of someone's pocket is lost. A wallet accidentally left on a table in a restaurant is mislaid.
At common law, a person who found lost personal property could keep it until and unless the original owner comes forward. This rule applied to people who discovered lost property in public areas, as well as to people who discovered lost property on their property. Mislaid property, on the other hand, generally goes to the owner of the property where it was found. Thus, for example, a person who finds a wallet lost in the street may keep it. If, however, a person finds a wallet inside a barbershop, the shop owner might have a better claim to the wallet. The basic theory behind this distinction is that owners of mislaid property are more likely to remember where the property is. Allowing property owners to keep it makes it easier for the true owner to recover the property.
Real property may not be lost or mislaid.
Many jurisdictions have statutes that modify the common law's treatment of lost or abandoned property. Typically, these statutes require lost personal property to be turned over to a government official, and that if the property is not claimed within a set period of time, it goes to the finder and the original owner's rights to the property are terminated.