This is a moderately common idea and if your jurisdiction has a "community gardens" type program, they may or may not be able to help. There was a local project here in Portland a few years back wherein a group of folks at PSU did an inventory of such lands with an eye toward using land more productive, as detailed in a documentary film and at DiggableCity.org

The person here on Tribe to ask about this is probably Kevin Balmer at people.tribe.net/heaveekevee Tell him that Rory sent you. He loves me more than Jesus, and owes me.

Is there an agricultural extension in your area? Many states have special offices associated with a land-grant university or agricultural department of some sort, and these may or may not know how to help open doors.