When the invasion came by John Butler at the Battle of Wyoming, Hollenback was among the foremost who sprang to their arms, and prepared to meet the foe.
With hopeless odds facing them, Hollenback was among those who escaped to the river, swam to Monocacy Island, and then to the eastern shore.
Foreseeing the necessity of instant aid from abroad, mounting his horse, he rode all night, gave information to Capt.
On the passage by the Connecticut Assembly of a resolve, allowing Wyoming to make their own powder, Hollenback was looked to, to provide the requisite machinery.
His arrival with the "Pounders" was spoken of by Mrs. Jenkins, with exultation, as an important event; for previously powder for the settlement was chiefly brought from Connecticut on horseback.
Hollenback died on 18 February, 1829, age 77, leaving to his children and grandchildren a large property, variously estimated at from US$300,000–$400,000.