A couple of weekends ago, I took a few friends out to help with volunteer work at Inks Lake State Park. While there, we observed various species, including this butterfly.
At first, I identified it as a Monarch, but upon further research and help from the iNaturalist community found that it is actually a Queen Butterfly (Danaus gilippus).
This species is found mostly in the tropics, as well as into temperate areas in the Americas, Asia, and Africa. Larvae feed primarily on milkweed and dogbane. When they mature, their feeding preferences broaden, while sometimes still occasionally found to feed on milkweed. This species also has chemical defenses that make it unpalatable to predators.
My iNaturalist post can be found here.
References: http://www.inaturalist.org/taxa/51743-Danaus-gilippus