The words "Don't Tread on Me" appears on the Gadsden flag below a coiled rattlesnake that is ready to strike. The flag was named after Christopher Gadsden, an American general and statesman, who designed the flag in 1775.

Prior to the American Revolution, the rattlesnake was a favorite animal emblem to symbolize American ideals and society, along with the American bald eagle and the American Indian. As the revolution continued to foment, the rattlesnake was used more to symbolize the 13 colonies.

The original Gadsden flag design features the coiled snake in the center of a predominantly yellow background. Some Gadsden flag versions have no apostrophe between the letters "N" and "T," and grass below the coiled rattlesnake may or may not be present in some renditions. The coiled rattlesnake also traditionally faces to the left, but there are versions that have the snake poised to strike to the right.

Considered as one of the earliest American flags, the Gadsden flag was revived numerous times and it has come to symbolize American patriotism, dissension with the government and calls to respect civil liberties. The American Tea Party movement in 2009 has adopted the Gadsden flag as its official symbol, displaying it at Tea Party movement rallies. Because of this association, the Gadsden flag is being regarded by some lawmakers as a political symbol.