Adams County was formed from part of Pickering County on April 2, 1799 some eighteen years before Mississippi was admitted into the Union. The County was named in honor of the second President of the United States, John Adams. The county seat is Natchez, a city with a colorful history relating to the life on the river known as "Big Muddy", gambling, and antebellum homes. Some historians believe that DeSoto and his men visited this area in 1543 and DeSoto may have died and been buried in Lake St. John, west of what is now Natchez. The majority of historians however, believe DeSoto was buried in present day Lake Village, Arkansas.
The French built Fort Rosalie in 1716 at present-day Natchez, Mississippi, an area occupied by the Natchez American Indians. Sited close to the main Natchez settlement, called the Grand Village of the Natchez, Fort Rosalie served as the primary French stronghold and trading post among the Natchez. Growing tension between the French and the Natchez erupted into violence several times during the 1720s, resulting in a massive attack by the Natchez on November 28, 1729. Fort Rosalie was wiped out, hundreds of settlers were killed and hundreds more taken captive. Fort Rosalie was captured and occupied by the Natchez until counter-attacks by French and Choctaw forces in 1730 forced the Natchez to evacuate. By 1731 most of the Natchez had been captured, enslaved, and shipped to French plantations in the Caribbean. Some escaped to live among the Chickasaw, Creek, and Cherokee.
In 1763 the French ceded the area to Great Britain with the Treaty of Paris. Under the Union Jack, Fort Rosalie's name was changed to Fort Panmure. The Adams County area remained under British control until the ambitious Don Bernardo de Galvez, Spanish Governor of New Orleans, decided to take advantage of her weak and unprotected condition. In 1779 de Galvez marched his army northward and took Baton Rouge and Natchez.
The 1795 Treaty of Madrid named the 31st Parallel as the boundary between the United States and the Spanish possessions, however it was not until 30 March 1798 that the Spanish actually turned the fort over to American forces.
In 1802, the territorial capitol was moved from Natchez to the town of Washington, about five miles east. This was done to avoid epidemics which often occurred in the port city. Then on April 9, 1803, Natchez was incorporated as a city of the United States.
In 1817, the Mississippi Territory was organized as a State. The convention met in the town of Washington and it was decided to move the capital to a more central location. Thereafter, Natchez began to lose much of the political prestige she had formerly enjoyed.
Though the steamboat era was still young , Natchez slowly came to be one of the greatest cotton ports of the world. Many slaves were brought in and planters operated vast estates, amassing unbelievable fortunes. During this time Natchez reached a peak of wealth and culture never surpassed in America. The Mansions of the period were erected on a grand scale and liberal living became a common custom. Many of these homes still exist today allowing us a glimpse at what was a magical time in the area's history.
On the outbreak of the Civil War, Natchez was still a rich agricultural center. The town furnished many soldiers to the Confederate cause, most prominent of who was Major General William T. Martin. Natchez was bombarded by the USS Essex in July of 1863, and later occupied by Ransom’s Brigade.
Civil government was suspended in Natchez from November, 1863 until August 9, 1865. The war destroyed the fortunes, freed the slaves, and the economic as well as the social structures were overturned completely. Natchez never regained the river trade that once helped make it rich.
For three generations the population increased little, but changes in the town were made with material improvements that blend with rather than destroy the still cherished past. In 1881, telephone lines were installed, and five years later, Judge Thomas Reber built a street railroad from the ferry landing on Main and St. Catherine Streets to the “Forks-of-the-Road.” The judge also installed the first electric light plant in 1886 in order to furnish lights for a casino, and Natchez had begun its climb back to become, once again, one of the Queen Cities of the lower Mississippi.
The county has a total area of 486 square miles, of which 460 square miles is land and 26 square miles (5.34%) is water. The population recorded in the 1800 Federal Census was 4,660. The 2010 census recorded 32,297 residents in the county.
Neighboring counties and parishes are Jefferson County (north), Franklin County (east), Wilkinson County (south), Concordia Parish, LA (southwest), and Tensas Parish, LA (northwest). Communities in the county include Natchez, Morgantown, Pine Ridge, Sibley, Stanton, and Washington.