The layer identifies corn, soybeans, grass, coniferous forests, structures, and other identifiable landcover. About half the state is complete and available for download. All counties colored yellow in the below map are completed and available. In the DNR GIS Library navigate to the county folder of interest and download the file beginning with "HRLC_2009". The legend will give you a general idea if your portion of the state is close to complete.
If you have any need for a landcover information, download a county and test it out. It might prove pretty useful!