Every state, plus the District of Columbia, has unclaimed-property programs. State law defines when a bank account is considered unclaimed or abandoned. Most state programs look at whether there has been any customer-initiated activity or contact within the last three to five years.
Before sending the account balance to the state, the bank is usually required to try to notify the customer. Some banks publish the names of the account holders in a local newspaper. Some banks send a letter to the last known address of the account holder. The bank turns over the account balance to the state if there is no contact from the account holder. This is known as escheatment.
You can find more information on unclaimed property programs through the National Association of Unclaimed Property Administrators (NAUPU) or through your state's unclaimed property office.