[4] The area was part of the territory in Tennessee that was previously legally recognized as belonging to the Chickasaw Native Americans as "Indian Lands".

[7] Around 1823, Louis Philippe I stopped briefly near the mouth of the Obion River and killed a bald eagle.

Alexander McCullouch, a War of 1812 veteran who served as aid-de-camp under John Coffee at the Battle of Horseshoe Bend, moved his family in the late 1820s to a plantation west of Dyersburg from northern Alabama.

His youngest daughter, Adelaide, married Albert Pierce, a prominent steamboat agent on the Forked Deer and Mississippi Rivers in the Reconstruction era.

[10] McCullough also had multiple sons that served in the American Civil War; Alexander Jr. who served as a colonel and head of the Dyer County Militia, Benjamin, who (according to family lore) learned to hunt bears from Davy Crockett and tried to follow him the Alamo but failed and also was killed at the Battle of Pea Ridge, and Henry who served in the Texas Rangers and married into the Ashby family of True Women fame.

A 54 mile railroad gap between Trimble and Covington (in Tipton County) continued to exist until 1882, when the Chesapeake, Ohio, & Southwestern Railroad finished construction on the line to give Dyersburg a rail connection.

[13] This line was leased to the Newport News & Mississippi Valley Railroad to operate two years later.

[17] On February 1, 1916, a black man named Julius Morgan was accused of raping a white woman in Dyer County.

"[21] Musician Noah Lewis was said to have named his song "Minglewood Blues" after the town of Menglewood.

[25][26] Dyer County is bisected by U.S. Route 51, the older major highway connecting Memphis with Chicago from south to north.

Burks Broadcasting - 100 Jack-FM / Eagle 97.3 / WTRO[39] Interstate 155 (Missouri–Tennessee) connects Dyersburg and the communities of Lenox and Big Boy Junction with the Missouri Bootheel via the Caruthersville Bridge, which crosses the Mississippi River at Boothspoint.

Tennessee State Route 78 connects Dyersburg with Nauvoo and Bogota before moving north to Lake County.

The Canadian National Railway's Gulf Division runs through Trimble, Newbern, and Dyersburg to connect with Memphis to the south and the wider CN rail network to the north.

Amtrak's City of New Orleans stops at the historic Illinois Central Railroad depot in Newbern twice a day.

Anti-Catholicism allowed Richard Nixon to carry the county narrowly in 1960, then after the massive revolt against the Civil Rights Act and race riots segregationist Alabama Governor George Wallace carried the county in 1968 and Nixon defeated George McGovern three-to-one in 1972.

Since then the county has become increasingly Republican except when Southerners Jimmy Carter and Clinton headed the presidential ticket.