Walk around often between dusk and dawn. When you see foxes, note the areas and the directions they are going. Revisit these places often. You will find they follow roads and trails, but they also tend to travel along natural trails like along creeks and dry creeks. Dens will be in slightly lowered depressions of higher elevations where water won't pool among shrubs and copses, in unkepmt yards. You can follow tracks in the snow in winter. You will know you are very, very close when you see litters of adolescent kits in the spring. Often you will see kits run right into the dens while the mom barks at you. You may be chased. Please don't bother them. They eat your mice and rats for you.