I just did a post on my website about Oak Forest Lot & Land Prices.
For you engineer types, I attached a atable showing sales in the last 6 months. Prices average $38/SF. This puts lot values at $225K to $442K. Obviously depending on size and location. Location is always critical. People building big new homes want to be near other nice homes and NOT close to anything ugly or commercial.
You won't find vacant lots in Oak Forest or nearby Garden Oaks. These are all tear-down properties.. May of the homes are quite liveable. In years past they would have sold to first time buyers, or people wanting to remodel. Now individuals or builders are buying them to demolish.
So, if you are searching for a building site in Oak Forest do a lot search of course, but 95% of the properties will be listed as single family homes being sold as lot value.
If you are unfamiliar with Oak Forest, please see my page on the neighborhood with home sales, home prices, price trends, house style, history and more. Oak Forest Homes.
My website has several other nearby neighborhoods such as Garden Oaks, the Heights, many more.