Mr.Momof3, Rockville Centre is a self-governing village in the Town of Hempstead and Oceanside is a hamlet that is governed on an at-large basis by the Town of Hempstead.
In case you are unfamiliar with the local geography:
What people refer to colloquially as "towns" are actually villages and hamlets, which are within actual towns; and, because villages and hamlets are referred to as "towns", then, many times, the error is compounded when actual towns are referred to as "townships".
Also, many colloquially refer to a "downtown business district" in a hamlet as a "village".
//www.city-data.com/forum/new-y...-glossary.html and
//www.city-data.com/forum/long-...-resource.html may be of some help to you in understanding the geography of "Lawn Guyland".
//www.city-data.com/forum/long-...you-think.html may help you understand the great geographic confusions caused by non-conforming ZIP Code postal zones.
You can get a fact sheet for any city, village or hamlet on Long Island by going here
American FactFinder and input the name of the city, village or hamlet for "city/town" (leave out the ZIP Code) and New York for "State", and then click "GO".
You'll get a lot of demographic, and some economic, statistics for the city, village or hamlet you selected, and if you click on "Reference map" (it's on the right hand side), you'll get a map.
When you do find a house that you like, you can find out in which community (city, village or CDP) that house is actually located, which is oftentimes different from the community named in that house's mailing address, by using the Census Bureau's
online address search function. (CDP or
Census
Designated
Place is the Census Bureau equivalent for a hamlet in Nassau and Suffolk Counties.)
And, very importantly, among other things, the Census Bureau's
online address search function also indicates in which school district an address is located.