Hi, be very careful with generalized answers, there is not such a think as an average value, not for a home, nor for a piece of land, it would make it very easy if that would be the case...
For land in particular you must do careful research with the help of an experienced Realtor.....
Zoning is very important, and any plans for changes in that area (road construction, or other changes from
residential to commercial or vice versa) are important factors..... If you are selling the land you should be
as informed about your land as the potential buyer, as that buyer will try to get all information available before
committing to even make an offer on the land.
So careful try to find out as much as possible, the local building commissioner can be of assistance and
then the experienced Real Estate agent in the area.
Good Luck to you
Edith YourRealtor4Life! And Chicago/NorthernIllinois & North Shore Expert
Working always in the very BEST interest of her clients