Loudon County, one of the youngest counties in Tennessee, was formed on May 27, 1870 from portions of Roane, Monroe and Blount Counties. Originally, it was named Christiana County, but a few days later the name was changed to Loudon in honor of nearby colonial Fort Loudoun. The fort was named for John Campbell who was the 4^th Earl of Loudoun and a commander of the all British forces during the French and Indian Wars. Several earlier attempts to form this county failed due to the difficulty in satisfying the general provisions of Tennessee's old constitution. The act to establish this county was first act ever approved by a governor of Tennessee. Governor D. W. C. Senter signed this act into legislation on June 2, 1870, and Loudon County was born. 

      In August 1870, the county officers were chosen. On September 5, 1870, the county court was organized at the Baptist Church in Loudon. This church became the temporary quarters of the county court until the new building, built by J. W. Clark & Brothers, was finished in 1872. The Loudon County Court House is on the National Register of Historic Places and is still in use today.

      The first settlers of Loudon County were the Overhill Cherokee Indians who built their villages along the banks of the Tennessee and Little Tennessee Rivers. The first white settlers were English soldiers, many of whom had families garrisoned in Fort Loudoun. The white settlers built opposite to the Indian settlers.

On October 25, 1813, the Tennessee State Legislature passed an act that established the town of Morganton on land owned by Hugh and Charles Kelso. Originally named Portville, the name of the town was later changed to Morganton to honor the Revolutionary War soldier Gideon Morgan, Sr. Morganton was the third incorporated town in Tennessee. The town was thriving until the L&N Railroad came through in the late 1800s and put an end to the river trade. The town eventually died out.

       As the railroad came through Loudon County, the river city Morganton faced economic decline and eventually died out. Greenback, on the other hand, was born and began to flourish. Originally, the site of Greenback was a field owned by Robert Thompson and J. B. Hall. The residents wanted to name their new community Alleghany Station or Thompson Station. However, the Post Office Department refused their requests because of other post offices with the same name. The name selection process was then moved to the Senate, and the name Greenback was chosen. The railroad was completed in 1889, and the first passenger train service was established in 1890. A second railroad depot, the L&N Depot was completed in 1914 (this building is now a warehouse). These two railroad lines brought economical growth to the small community of Greenback and helped to firmly establish Greenback as a thriving community.

      The first bank in Greenback opened for business on January 12, 1912 but closed in March 1931 due to the depression. The Greenback Flour Mill was build in 1919, destroyed by fire in 1929, and rebuilt later that year. The first school opened in Greenback on August 7, 1921 and consisted of only six rooms and an auditorium. 

       Lenoir City originated from lands owned by General William Lenoir. General Lenoir was born in Brunswick County, Virginia on May 8, 1751 and moved to North Carolina in 1759. During the Revolutionary War, he served as captain under Colonel Cleveland in the Battle of King's Mountain. As a reward for his services during the war, the state of North Carolina awarded him 5000 acres located along the northern bank of the Tennessee River. This tract of land, known as the Lenoir tract, stretched a distance of two miles.

       In September 1809, General Lenoir deeded his land to his eldest son, Major William Ballard Lenoir. Major Lenoir named the land Lenoir's Station (then located in Roane County) and moved onto with his wife in 1810. Major Lenoir and his family first moved into a log house built by Judge David Campbell. By 1821, the farm had been cleared, and the Lenoirs built and moved into a larger brick home. This property remained in the Lenoir Family until 1876.

In 1890, the Lenoir City Company was formed by several prominent businessmen in Knoxville and New York City in order design and built the new town. They surveyed the land and divided it into lots and streets. Many of the first homes were purchased from the Lenoir City Company. In 1907, Lenoir City was incorporated by an act of the state legislature. The first mayor was F. A. Weiss, the town's first millionaire.

       In 1790, families began settling on the northern bank of the Tennessee river. A few of these settlers included the Tunnels, the Carmichaels, and the Blairs. By 1835, James, John, and Wiley Blair had built a steamboat landing, a store, and several houses. They named their new settlement Blair's Ferry. The first steamboat to pass up the river was the Atlas in 1828. However, it was not until about 1835 that steamboats began regularly stopping at Blair's Ferry.

      Standing on the waterfront was a storehouse built by James Blair in 1834. Due to certain provisions in the Hiwassee Purchase, a Cherokee Indian named Pathkiller claimed the store, the ferry, and the land on which the town of Blair's Ferry was located. Blair was ordered off the land, and Pathkiller became its new owner. Blair filed suit in the Tennessee Supreme Court, and a fifteen year court battle ensued. Blair eventually won his lands back from Pathkiller but died shortly after, leaving his entire estate to Wiley Blair. In 1851, sensing an opportunity for profit, Wiley Blair laid out a town and dubbed it Blairsville. Unfortunately, he failed to sell any lots, and the next year he was forced to sell the land to S. M. Johnson & Company.

With the advent of the railroad in 1848, this small community rapidly began to grow. Between the years of 1852 and 1856, a railroad bridge was built across the Tennessee River. The bridge opened for traffic on March 17, 1855. With both a railroad terminus and a steamboat port, Blair's Ferry became a popular site for transferring merchandise and produce from the river to the railroad. In 1858, the name of the town was changed to Loudon. Due to its quick economic growth and central location within the county, Loudon was chosen as the county seat.

       Philadelphia is both one of the oldest and newest towns in Tennessee. During the fall of 1821, William Knox and Jacob Pearson laid out a town about six miles south of Blair's Ferry. Originally, the town was located in Monroe County. Philadelphia was not incorporated until April 28, 1968.

      On February 17, 1836, the Tennessee General Assembly granted the Hiwassee Railroad Company permission to build a road from Blair's Ferry to the Tennessee-Georgia Line. Once the construction of this road was announced, land speculators began to visualize that Philadelphia would become the major commercial center located enroute between Knoxville and Chattanooga. To encourage growth, advertisements in publications announced Philadelphia as a possible industrial center and encouraged people to relocate to this town. In fact for many years, the railroad served as a vital link in Philadelphia's progress. Vast quantities of grain and livestock were shipped from Philadelphia via the railroad. However, with the construction of the railroad bridge at Loudon and improved transportation routes, the use of the stockyard and depot declined steadily until they closed in 1952.