Harnett was formed in 1855 from Cumberland County. It was named in honor of Cornelius Harnett, an eminent Revolutionary patriot, president of the Provincial Council, president of the Council of Safety, delegate to the Continental Congress, and author of the Halifax Resolutions of April 12, 1776. It is in the eastern section of the State and is bounded by Chatham, Cumberland, Hoke, Moore, Lee, Wake, Johnston, and Sampson counties. The present land area is 595.01 square miles and the 2000 population was 91,025.

The courts were ordered to be held at Summerville until a courthouse was erected unless otherwise directed by a majority of the justices of the peace. It also named commissioners to locate the geographical center of the county, acquire the land, lay out a town, and erect the public buildings. The town was called Toomer in honor of John D. Toomer of Cumberland, a judge of the superior and of the supreme court. Many people became dissatisfied with the location, and in 1859 an act was passed to allow the voters to decide whether Toomer should remain the county seat or to select a new location. If a new site was selected, it should be called Lillington. Lillington was named in honor of Alexander Lillington. It is the county seat. 

During the Revolutionary War, the Scots, who were forced to take ironclad vows never again to take up arms against the British, were considered as traitors. Since their activity assisted the British against the American Patriots, public executions were not uncommon. One site near Lillington was the scene of a mass execution of Scot "Traitors."

One of the last battles of the War Between the States took place at Averasboro near Erwin. General Sherman's army, on its march to the sea, defeated the army of General Hardee and proceeded eastward. The centennial celebration of that event was held at the site of the battlefield in 1965.

Only after 1880, did the population begin to establish itself in urban rather than rural areas. Lillington, Dunn, Coats, Angier, and Erwin became trading and commercial areas. Today more than one-fifth of the population resides in towns or villages. Agriculture and agricultural products are the greatest source of income to the county. The preponderance of the population is either engaged directly in agriculture or derives a major portion of its income from the economy created by agricultural pursuits.

Harnett County is now moving into the industrial development phase. Community planning is being undertaken on an unprecedented scale and new leadership is emerging which holds promise of broadening the county's economic base. The western and southwestern portion of Harnett County could easily become the playground of east-central Carolina. The terrain, the geological character and its proximity to large and growing metropolitan areas place this portion in an excellent competitive position. History is made by people, and the people of Harnett County accept the challenge that tomorrow shall hold unlimited opportunity.