From Stamps of the World
Hillegom is a town in the western Netherlands, in the province of South Holland. The name Hillegom is derived from the abbey named Hijlighem (Old Frankish for "Holy Home"). This abbey no longer exists. Hillegom is part of an area called the Duin- en Bollenstreek ("Dune and Bulb Region"). As such, a large portion of the local economy was traditionally geared to the cultivation of bulb flowers.
Read more @ http://en.wikipedia.org/wiki/Hillegom