Palmyra, Missouri

Palmyra was platted in 1819 and named after the ancient city of Palmyra in Syria. The settlement was designated county seat in 1827. A post office called Palmyra has been in operation since 1830. 

In 1862, the city was the scene of the Palmyra Massacre, in which ten Confederate prisoners were killed in retaliation for the disappearance of a local Union man.

Wikipedia