Go to Find-A-Haunt.com. I have posted there. Also people have posted on Craigslist too. Could not remember but also Scary Events. com is another one.
My haunt group has a map, but other than that I can't say that I advertise other than word of mouth. I live in a cul-de-sac and the only reasons to drive in to it are because you live there, you know someone who lives there, you're coming to see my haunt or you are driving by looking for open garage doors so you can do a grab and dash. I tend to think that putting flyers up encourages the latter.