I am looking it up right now...

It's an Army National Guard Patch of Florida.

"Worn from: 17 June 1948 - Current.

The design of the insignia reflects the early history of Florida. The white trace outline is that of "Castillo de San Marcos, " a masonry fort (begun in 1672) built by the Spanish to protect Saint Augustine. Founded in 1565, Saint Augustine was the first permanent European settlement in the continental United States."

Source:

http://www.vetshome.com/army_national_guard_patches_his_1.htm

Christoph

^{Hello Marion and Christoph,}

Thanks for checking.

Patchman