The Continental Army under General George Washington camped here during the winter of 1777-78 under harsh conditions. It's now a very pleasant national historic park with many monuments, an extensive visitors center, and restored structures including the faithfully detailed house in which Washington and his staff were quartered. Costumed interpreters provide expert commentary.
If you go:
Bicycling is an excellent way to tour the park.
Links:

1400 North Outer Line Drive
King Of Prussia, Pennsylvania 19406 USA
Phone Numbers:
Visitors Center
+1 (610) 783-1099
+1 (610) 783-1099