Smithfield is a town in Johnston County, North Carolina, United States. In 2010, the estimated population was 12,965. It is the county seat of Johnston County. The city is home to the Ava Gardner Museum and is situated along the Neuse River, where visitors enjoy the annual Smithfield Ham & Yam Festival, walks along the Buffalo Creek Greenway and the historic downtown district. The town is located in North Carolina's famed Research Triangle and is approximately southeast of downtown Raleigh. The Raleigh-Durham-Cary Combined Statistical area has a population of over 2 million residents.