Portsmouth is the county seat of Scioto County, Ohio.
The first permanent settler from the newly independent United States to live in the vicinity of what would become Portsmouth was Emanuel Traxler in 1796. Henry Massie formally laid out Portsmouth in 1803. He named the town Portsmouth after Portsmouth, Virginia. Located at the intersection of the Ohio River and the Scioto River, Portsmouth grew quickly due to the traffic on the rivers. Polly Barber became the first child to be born in Portsmouth in 1804. The town continued to prosper with the construction of the Ohio and Erie Canal during the 1820s and the 1830s.
Portsmouth's growth resulted in the town becoming the Scioto County seat. By the late 1840s, approximately 2,500 people lived in Portsmouth. There were at least four churches, two newspapers, and seventeen stores in the town. There also was a series of dry docks to repair and build steamboats.
By the late 1880s, Portsmouth had sixteen churches to meet the needs of its twelve thousand people. There also were four banks, a machine shop, a brewery, steel and iron business, several clothing and shoe manufacturers, a stove company, numerous quarries, and several businesses affiliated with the railroads. Brick-making also was a successful business at this time. A number of companies produced bricks. The largest and most profitable establishment was the Scioto Valley Firebrick Company that was established in 1871. By 1916, these companies could produce more than two million bricks per day.
During the late 1800s and the early 1900s, several other business ventures were begun. The Portsmouth Street Railroad and Light Company offered trolley service between Portsmouth and New Boston beginning in 1893. Mitchellace became a major manufacturer of shoelaces during the first decades of the 1900s and the Selby Shoe Company opened for business in 1906. Portsmouth became an industrial community by the early 1900s while agriculture continued to be the major occupation of most Scioto County residents.
During the late 1800s and the early 1900s, Portsmouth residents enjoyed a booming economy and a rich social life. In 1897, the Enos Reed Pharmacy was the first business in the town to sell Coca Cola. Buffalo Bill Cody's Wild West and Congress of Rough Riders visited the community in 1900. The Portsmouth Library opened its doors in 1902 with the help of funds donated by Andrew Carnegie. T.A. McMahon of the Salvation Army waged his own war against the numerous bars operating in the city in the first decade of the 1900s. Football also was important to the town's residents. In 1909, the Portsmouth Shoemakers played the New York Giants. The Portsmouth Presidents and the Portsmouth Merchants were organized as semi-pro football clubs in 1926. The Portsmouth Shoe-Steels joined them the following year with Jim Thorpe as the team's coach. In 1928, the Portsmouth Spartans joined the National Football League.
The years of the Great Depression of the 1930s were difficult for Portsmouth. Even more disastrous was the flood of 1937. The Ohio River crested more than twenty feet above flood stage. The flood left thirty-five thousand residents homeless and destroyed sixty percent of all of the homes in the community. The people of Portsmouth rebuilt their town and World War II once again brought prosperity to the community. Henry Oberling Motor Company opened its doors in 1950. Beginning in 1956, the uranium enrichment plant at Piketon also provided a number of Portsmouth residents with employment. The Ohio Stove Company also doubled production in 1964. In 1973, the completion of the Southern Ohio Correctional Facility at Lucasville brought new job opportunities to Scioto County residents.
Despite these new businesses, Portsmouth has faced a continuous decline in population ever since the 1950s. In 1950, more than thirty-six thousand people lived in the city. Fifty years later that number has declined to twenty-two thousand. Today, Portsmouth is home to Shawnee State University. In addition, Portsmouth is also known for a series of murals painted along its Ohio River flood walls. These murals depict the community's history from prehistoric times to modern day.