The nz,cz dividing line is I-80.
Biotroller hunts the DesPlaines Conservation Area which is in the cz south of I-80.
Strangely though, DCA is considered part of the special Northeast Zone for the early Sept. season.
An influential land-owner/duck-hunter, tried to get the DNR to meander the logical nz,cz boundary south of I-80, around DCA and his private flooded fields, and then back up to I-80. His fields would now be in the nz. This would allow an earlier start to his season and first shot at the local birds. He would also avoid any early freeze-up prematurely closing down his hunting. It failed due to public outcry from hunters at the local advisory board meetings.
(Curiously each zone's waterfowl advisory committee was disbanded by the state the following year. You might speculate it was because they provided the only place where vocal opponents of the zone change were able to protest such an unfair proposal wreaking of political favoritism).
Imagine the additional confusion a meandering boundary over several counties would have caused when you throw the quota zones and need for reporting of the kill and punching a ticket into the mix? All the usual regs, phone reporting, ticket punching, etc, etc, ... plus now you would probably have to have notarized gps coordinates of the exact spot a dead bird fell for reporting purposes, and a legal representative all available for any CPO checks in the field!
Home of the free... BECAUSE OF THE BRAVE !