Millerstown is located on a tract of land originally sold as "Smithfield" to James Gallagher on September 23, 1766; there is evidence, however, that he had lived in the area prior to his purchase.

[5]: 1010 This plot of ground was later deeded to David Miller on September 1, 1780, who established a settlement and a ferry operation.

[5]: 1010–1 [6] In 1800, the first tavern was constructed on Market Street, later known as the Alexander House, which would in more recent years become a VFW Post until its closure in 2017.

[6][7] Millerstown Borough was incorporated February 12, 1849, and the first meeting of the newly formed town council was held on April 14, 1849.

Abraham Addams was the first chief burgess (mayor), and John M. Cauffman, Christian Beck, James R. Gilmer, and Jacob Emerick, were members of the first borough council.

[6] Millerstown is located at 40°33′3″N 77°9′17″W / 40.55083°N 77.15472°W / 40.55083; -77.15472 (40.550884, -77.154659),[8] along the Juniata River in northern Perry County, at the junctions of U.S.