neighbor on
To lie or exist immediately adjacent to something else. The two countries both neighbor on a piece of land they both claim as their own, which has been the source of constant warfare and skirmishes over the years. It's a beautiful house, but once we found out it neighbored on a municipal dump, the extremely low price made sense.
neighbor on something
to be directly adjacent to something. Our house neighbors on a park. The park neighbors on a stretch of beach.