I'm not sure what type of camping you are doing, but i enjoy Turkey Run state park. I OCed last 2 years with no problems from other campers.
Check the website in ElsiePeaRN's post. It has maps that show the ACoE project boundary for each lake/park. Outside of that boundary is DNR/State. Inside of that boundary is ACoE. Notice, that most project boundaries include ALL of the water, spillway, dam, and shoreline. The DNR may patrol it, but the property is ACoE.
I've written to our District Commander (Colonel Kieth A. Landry) asking that the ACoE adopt the same recreational property rules as the National Parks and National Forests (carry as per state/local laws). Have you?
Need to call for sure, but if that's your real badge in your avaitar, I bet it's a trump card!
Your answer is here in the indiana code http://www.in.gov/legislative/iac/T03120/A00080.PDF
Go to code 312 IAC 8-2-3 it states, "
Sec. 3. (a) A person must not possess a firearm or bow and arrows on a DNR property unless one (1) of the followingconditions apply: ...
with a valid unlimited license to carry a handgun:(i) issued under IC 35-47-2-3;"