Organic methods involve pouring a couple gallons boiling hot water into anthill; follow with water containing citrus peelings, borax and sugar mixed, mint plants/mint tea spray, sprinkle grits on anthill.
An ant hill nest can be poisoned with any off-the-shelf product or with gasoline. The best solution is to use an ant bait like AMDRO. AMDRO is available at most home improvement stores. The ants will injest the bait and take it back to the their nest and kill the entire nest and the queen.
well if your are getting rid of an ant hill in your yard the best thing to deal with it is to pour two cups of club soda that carbonated water in the ant hill because carbon dioxide in the water is heavier then the air and will displaces the oxygen which will kill the ant queen and ants.