[2] The county was officially organized on February 10, 1851, and is named after state representative Lewis Dent, a pioneer settler who arrived in Missouri from Virginia in 1835.

Henry Rowe Schoolcraft was one of the earliest visitors to the area that would become Dent County, which was then unmapped and unknown.

They first headed west from Potosi on a trail that is now followed by Highway 8, then turned south through southern Dent and Shannon counties, where Schoolcraft found the Current River, "a fine stream with fertile banks and clear, sparkling water.” Today the river attracts tourists who launch canoes by the thousands during the summer to enjoy the fast-moving water of the Current and Jack's Fork Rivers in the Ozark National Scenic Riverways.

Schoolcraft traveled to the area of today's Springfield, Missouri, then went east on White River and finally back to Potosi, completing a journey of 89 days.

The "trace" wound from Sligo southwest to the Ephraim Bressie Farm on Spring Creek north of Salem.

An abundance of waterpower and difficulty of transportation made mills important in the settling of the new land.

William Thornton, Daniel Troutman and Daniel M. Wooliver were among the 1829 settlers, followed by William Blackwell, Nicholas Berardy, Elisha Nelson, Jerry Potts, Ephraim Bressie, Robert Leonard, Abner Wingfield, Lewis Dent, Wilson Craddock, Thomas Higginbotham, Jack Berry, Silas Hamby, Smith Wofford, Turquill McNeill, Dr. John Hyer, Samuel Hyer and David Lenox.

The first mayor of Salem was appointed or elected just after the Missouri state legislature passed the laws relating to village government in 1860.

An earlier log courthouse, built around 1851 or 1852, was Dent County's first, on the Wingfield farm northeast of Salem.

Elmer in his history reports that when the courthouse was finished, pictures of it were published in McClure's Magazine and newspapers in the East to show the development of the West.

Sligo was the fourth iron works built in the state, following Meramec, Midland and Nova Scotia.

The Sligo & Eastern Railroad ran a branch to East End to gather wood for the kilns producing charcoal for the furnace.

In recent times, the largest mining and milling operations were in the "New Lead Belt" some 30 miles (48 km) east of Salem.

Doe Run in nearby St. Francois County continues mining and battery reclamation in the area today.

When the generators could no longer meet the demand and were costly to operate the city contracted with Show-Me-Power Cooperative.

While the early lumber companies cut the vast Ozark pine forests, timber has remained a major asset, with white oak staves for barrels, oak flooring, pallets, charcoal briquettes and lumber.

Dent County has had its ups and downs economically, but is proud of its record of having five banks during the Great Depression without a failure.

Dent County's skilled labor force made needlework industries a natural.

After World War II the Industrial Building Corporation raised funds for the International Shoe Factory.

Today's largest employer in Dent County, U.S. Foodservice, is an institutional food business and began in Salem as Craig Distributing.

After World War II, Farris Craig started with a panel truck and peanut vending machines.

46% of Dent County residents are considered "Non-adherents" of religion (those who do not attend a particular church regularly) making this the largest single group in the survey.

On July 13, 2015, the county commissioners, Darrell Skiles (R), Dennis Purcell (R), and Gary Larson (R) voted unanimously to lower all flags to half staff every month on the 26th for a year to protest the Supreme Court decision regarding same sex marriage rights.

Smith won a special election on Tuesday, June 4, 2013, to complete the remaining term of former Republican U.S. Representative Jo Ann Emerson of Cape Girardeau.

Like most rural areas throughout Southeast Missouri, voters in Dent County generally adhere to socially and culturally conservative principles which tend to influence their Republican leanings.

The proposition strongly passed every single county in Missouri with 78.99 percent voting in favor as the minimum wage was increased to $6.50 an hour in the state.

In 2015, Dent County commissioners voted to officially mourn the US Supreme Court ruling which legalized same-sex marriage.

The flags at the Dent County Courthouse and the Judicial Building were to be lowered to below half-staff on the 26th of each month for a year.