[4] Its county seat is Hartsville,[5] with which it shares a uniquely formed consolidated city-county government.

[7] The prison became a hot spot for COVID-19 cases during the COVID-19 pandemic, giving the county the highest incidence rate in the U.S. in May 2020, with 1 in 7 residents known to be infected with coronavirus.

It was named for William Trousdale (1790–1872), Brigadier General in the Mexican War, Governor of Tennessee, 1849–1851, and U.S. Minister to Brazil, 1853–1857.

Hartsvillians had initially sought the creation of their own, separate county in 1849, but the effort failed.

There are photographs showing residents of the county canoeing in front of the flooded courthouse.

However, after the trains stopped running through the county, business slowed and suffered economically.

As of May 8, 1,284 prisoners at Trousdale had tested positive for the coronavirus, as had 50 employees and contractors at the facility.

As of the 2020 United States census, there were 11,615 people, 3,189 households, and 2,083 families residing in the county.

The only Republican presidential candidate to win the county before John McCain in 2008 was Richard Nixon in his 1972 landslide re-election.