Your county government may be the one in charge of mosquito control in public lands, so check with them or any other local authority about mosquitocidal treatment in the swamp area.
If you want to order the control yourself, I would recommend you contact a company that does mosquito control  because it is best to leave these things to professionals.  Conditions of the swamp area, and many other factors must be considered in choosing the method of control. 

Mosquito control is best done in the larval stage when mosquitoes are not biting anyone and they are confined to the water.  Having said that, one has to investigate what are the mosquitoes that are biting you,  and where they are breeding.  although the swamp is a probably the breeding site, some mosquitoes do not breed under swamp conditions, and the problem you have may be coming from other places.  Specialized technicians should be able to determine what is the best course of action.