I find this interesting as well. In Kansas we have many trails (as some of the large national trails go through Kansas), many historic sites and a national preserve. I wonder if there is some form of distinction that keeps the preserve from being considered a park. Something for me to look into.

Personal Audio Reading: No One Goes Alone by Erik Larson
www.penguinrandomhouse.com/books/688421...
Batty Book Club Read: Interview with the Vampire by Anne Rice www.penguinrandomhouse.com/books/153679...