The Moultrie Flag was raised during the Battle of Sullivan's Isl

https://blogfreely.net/branoryccv/honoring-their-memory-flying-flags-to-remember-why-they-fought

The Moultrie Flag was raised during the Battle of Sullivan's Island in 1776; showcasing a blue field with a palmetto tree and crescent moon, it symbolizes resilience against British attacks in defense of Charleston.