Fort Roberdeau also known as The Lead Mine Fort. The Fort can be viewed at any time between the hours of 8:00 A.M. and sunset for no charge.
Seasonal tours are available, May 1 through October 31, Monday – Saturday 10am – 4 pm and Sunday 1pm – 4 pm. $6:00 fee.
To claim a find, please post a picture of your party or a signature item at the front gate of the fort (Posted Coordinates).
History of the fort:
Standing before you is a reconstructed Fort Roberdeau, added to the National Register of Historic Places on May 29, 1974.
Why and How did Fort Roberdeau become a frontier fort during the American Revolutionary War?
The Why and How: During the early phase of the Revolutionary War, the American Continental Army struggled to supply the soldiers with food, clothing, rifles, & muskets, cannon, pack horses, and lead for the manufacture of small arms ammunition, for example, musket balls.
The solution for shortage of lead was to find domestic lead or sites and mine them. Sinking Valley, the valley of this location, came to the attention of Pennsylvania authorities. In the Spring of 1778, an expedition was organized from Carlisle under the direction of General Daniel Roberdeau to mine the local lead ore deposits in order to supply lead for the Army. General Roberdeau served as militia general and member of Congress from Pennsylvania.
On March 30, 1778, the Pennsylvania Assembly approved Roberdeau to visit the lands and gave him permission to mine the lead. The Fort was named after the expedition leader General Roberdeau and nicknamed after the purpose of lead mining. The bulk of fort construction took place from April to June 1778.
On June 4, 1778,Daniel Roberdeau reported to General Washington, "To prevent the Evacuation of the frontier and general defense against Indian incursions I have built with logs at the Mine in Sinking Spring Valley at the foot of Tussee Mountain, a Fort, Cabbin fashion, 50 yds. square with a Bastion at each Corner."
The cabin fashion was the horizontal log wall technique in front of you. Historians speculate that the ground here was too hard and rocky to allow digging a ditch for a more common stockade (vertical) wall fort of the day. The timbers were simply set atop each other to the desired height and served as a wall for the cabins which helped stabilize the structure.
The bastion serves a military purpose by projecting out past the fort walls at an angle to the wall, so as to allow to better survey around the fort and provide defensive fire in several directions. Simply, the bastion allowed a few men, perhaps only eight with two on post in each bastion, to survey and cover the entire area around the fort. A pracical design for the manpower challenges on the frontier.
A free self guided tour begins at parking, just follow the signs for the National Treasure, treasure hunt.You stand where history lives. The only dimension now separating you from the Colonists is time. Settlers called Sinking Valley home, as Native Americans and Rangers alike walked these grounds. You will now do the same.
Uncover a mystery centuries in the making. A free treasure hunt, it is available any time Fort Roberdeau's grounds are open to the public!
Begin your journey in the Fort's parking lot, where a solitary clue on a fencepost whisks you away on a ten-stop journey in pursuit of General Daniel Roberdeau's lost treasure.
Along the way, use your cunning and observation to find each new location. Fail to do so, and you will find yourself back in the parking lot where you began! If you succeed, your treasure is redeemable inside the Fort's gift shop (during business hours) for an even greater prize. Your challenge awaits!
There is also an interactive history and science lesson as simple as a stroll in the out doors, The Discovery Trail is available any time the grounds are open to the public for no fee. Learn about our solar system around the outer edge of the Bluebird Trail while key events during the American Revolution are posted along the inner side of the trail. Your trip begins at the posted coordinates for the trailhead.
Virtual Rewards 3.0 - 2022-2023
This Virtual Cache is part of a limited release of Virtuals created between March 1, 2022 and March 1, 2023. Only 4,000 cache owners were given the opportunity to hide a Virtual Cache. Learn more about Virtual Rewards 3.0 on the Geocaching Blog.