Property Lines & Homeowner Associations

There are many Homeowner Associations (HA) that have varying degrees of control over there residents, but a recent trend in our association is the encroachment onto our property which we pay taxes on. Is a HA able to run a sidewalk through your property or be on your property by a few feet on either boundary? My understanding is that the HA can restrict you from building a a fence a couple feet from the sidewalk, but I did not think they can put anything on your property. Anyone else have these problems?