The fort itself was constructed some time after Antes returned from his raiding. Having seen the need for proper defenses, wooden stakes that were to make up the outermost walls were driven two meters into the ground and extended four meters above the ground encircling an area of just under an acre. This new fortification was put to the test almost immediately when Indians attacked the surrounding area shortly after the fort's construction. Indians allied with the British were encouraged to attack any structures in Pennsylvania, and in June 1777 two settlers were killed in Indian attacks just across the river from Fort Antes. Soldiers who wanted to investigate the sounds of the attacks were instructed not to in case of an ambush. Disregarding their orders they crossed the river and found only one survivor. This was not the only incident of Native American attacks in the area, and life was especially treacherous for settlers encroaching on Indian land.
The Wyoming Valley massacre occurred in 1778, the loss of over 300 settlers at the hands of British and Indian forces prompted widespread fear, and attacks in the area of Fort Antes were becoming increasingly frequent and increasingly violent. This was the major trigger for the Big Runaway, in which Fort Antes and the surrounding areas were evacuated in fear of further Native American attacks. Robert Covenhoven, a former member of the Continental Army was the one who gave the order for Antes to evacuate before himself retreating to Fort Augusta. The abandoned property in the area was all burned. Fort Antes survived the fires due to it's peeled oak walls, and the Wallis House survived due to it's stone construction. The settlers were outraged at the loss, and insisted that they could have defended their homes from Indian attack with military aid.