You are looking for a small sized container at Upper Landing Park, which is part of the Walkway Over The Hudson.
*** If the elevator is not working, you will not be able to easily access this cache from the Walkway. Use the provided parking coordinates. ***
Upper Landing Park is a small park packed with lots of historical information. For example, the first deed for this area was signed in 1683. At that time, a Wappinger named Massany signed a deed giving control over the land around the mouth of the Fall Kill and the Slangen Kilp (“Snake Cliff”) to two Dutch settlers, Pieter Lansingh and Jan Smeedes. The two hoped to build a mill on the small creek running from the Pooghkepesingh falls. The Dutch eventually referred to this creek as the Val Kill.
Tho it looks it, this cache has not been around since 1683. Cachers in dress clothes can access this cache. There is no need to go around the fence. No poisonous plants were observed here, just grapevine and Virginia Creeper.
For details regarding the Taconic Region Geocaching Challenge, please see WOTH1 Hats off to Civil Engineers.