Plunketts Creek Township was formed from parts of Franklin Township, Lycoming County, and what is now Davidson Township, Sullivan County, by the Court of Quarter Sessions of the Peace of Lycoming County in 1838. The township was once much larger in size, but several townships in both Lycoming and Sullivan counties have been carved from its original boundaries. The township is named for Plunketts Creek, a tributary of Loyalsock Creek. The creek is in turn named for Colonel William Plunkett, a frontier doctor and militia officer during the pre-Revolution years in the Province of Pennsylvania. He was noted for his skill in dressing the wounds of pioneers who had been scalped during the French and Indian War. Plunkett was also a veteran of the Pennamite–Yankee War, which had pitted settlers from Connecticut to the Wyoming Valley of Pennsylvania against those who had been established in Pennsylvania prior to the Connecticut settlers' arrival. He received title to land at the mouth of the creek that is now named for him.