Shimek State Forest consists of several non-contiguous units comprising about 10,000 acres in Lee and Van Buren Counties. The most significant of these from an ornithological standpoint is the main parcel of the Croton Unit, comprising about 1,100 acres.

From the town of Donnellson at the intersection of Highways 218 and 2 in central Lee County, travel south about 2 miles on 218 to its intersection with highway 394. Continue south on highway 394 about five miles to the unincorporated community of Argyle. Turn right (west) at the only intersection and go about 2.5 miles to a fork. Bear right. Continue on this road about 1 mile to a parking area on the right, just before a small bridge. You may also continue past this point to the next intersection. Taking the road to the right will take you past more of the Croton Unit of Shimek State Forest.