Marie,
I looked at the 1870 census...each and everyone of the listings.I found Paterson/Passaic County under the Saddle River listing! (Under the Washington listing is the Saddle Brook listing!) I randomly looked at pages within each listing by 20's (pages) and found nothing for Wahwah. It seems that there is a town(ship) name and a Post Office name and what you want is the Post Office name. I have had the same problem in upstate New York and on Long Island. Unfortunately, I realized I had to go page by page to find what I wanted. : (
I found nothing in the census records for 1880.
I do not know where you are, but it seems the web address I gave you has census records and you can email them questions.
As I said before...Good Luck : )
Rose Mary