The present site of Alexandria was a natural one for settlement because of its location on the Red River. The river was not navigable above this point for many months each year due to the rapids. For practically half of the year (from July to January), Alexandria was at the head of navigation on Red River. During this time, boats could not ascend above this point due to the rapids in the river. All cargoes had to be transported by land around this impediment and re-shipped. In some seasons of the year, the upper river was so shallow that boats could not make the trip. As a result of this condition, a number of warehouses were built to store goods moving from South Louisiana to Western Louisiana and Texas. The merchants who owned these warehouses purchased the products that were brought overland to this point and supplied the planter and trader with the necessary goods.

The Red River and its tributaries were the main arteries of transportation for the area. In 1769, the section of what is now Rapides Parish was deeded by France to Spain. The Alexandria site developed rapidly as a trading post, serving as a center of traffic between the French, Spanish, English, Americans and Native Americans.

Each year the Mississippi, an Ojibwa Indian word meaning "big river" carries 400,000,000 tons of sediment into the Gulf of Mexico and discharges more water than all European rivers combined.

The growth of the lumber industry in the latter years of the 19th century and the opening of the area by the railroads allowed Alexandria to prosper immensely. The golden age of the “sawmill capital of the world” was dawning, with 75 mills operating within 40 miles of the town.

Through much of its early history Louisiana was a trading and financial center, and the fertility of its land made it one of the richest regions in America as first indigo then sugar and cotton rose to prominence in world markets. Many Louisiana planters were among the wealthiest men in America.

The Alexandria economy was greatly boosted during the First and Second World Wars when two large military installations were constructed nearby, Camp Beauregard and England Air Force Base.