The cities of Palmer, Wasilla, Houston have true zoning. Here are the zoning maps for Palmer, Wasilla, and Houston. These maps are similar to what we generally think about when we hear the term "zoning". The maps are also useful in that they delineate the city boundaries.
In the rest of the Matanuska-Susitna Borough there really isn't zoning in the traditional sense. The borough says that they do have zoning because they are trying to get everyone accustomed to the term. Eventually we will probably have zoning here. The borough government is certainly planning in that direction and is staffing the departments accordingly.
There are certain land use restrictions that are important to keep in mind. Some of the restrictions are borough-wide and some are different in different areas. Here is the borough page on their website titled "zoning" . Even though this isn't true zoning, it is very important to keep these land use restrictions in mind.
Included on the zoning page are Special Land Use Districts which are large areas of the borough that have specific restrictions. Some areas are much more restrictive than other areas.It is extremely important to check into these restrictions before you buy and before you build. In addition there are certain subdivisions that have borough designations as single family use, and others as large lot single family use.