Genuine Smithfield hams [are those] cut from the carcasses of peanut-fed hogs, raised in the peanut-belt of the Commonwealth of Virginia or the State of North Carolina, and which are cured, treated, smoked, and processed in the town of Smithfield, in the Commonwealth of Virginia.
The peanut feed stipulation was removed in 1966. The present statute specifies both process and method as follows: 
...Genuine Smithfield hams are hereby defined to be hams processed, treated, smoked, aged, cured by the long-cure, dry salt method of cure; and, aged for a minimum period of six months; such six-month period to commence when the green pork cut is first introduced to dry salt, all such salting, processing, treating, smoking, curing, and aging to be done within the corporate limits of the town of Smithfield, Virginia
The specificity of the statute ensures that the product is not pre-processed anywhere else, and only finished in Virginia, or the town of Smithfield. The locality of the curing process also ensures a uniformity in flavor, since during the curing and aging process the local environment's air quality, humidity, and the local varieties of airborne mold spores (whose enzymes are produced as a byproduct of growth on the ham's rind) produce a unique and repeatable flavor.
|This section requires expansion. (September 2011)|
The first record of the commercial sale of "Smithfield Ham" is a receipt for the sale of these cured hams to Ellerston and John Perot on the Dutch Caribbean Island of St Eustatius, dating from 1779.