John Harris Jr. (October 22, 1727 – July 29, 1791)[a], was an American frontiersman and politician who operated a ferry along the Susquehanna River at Harrisburg, Pennsylvania and was later instrumental in the founding and growth of the city and support of the State through wartime.

For many years, Harris Jr. and his family were considered the principal store keepers on the American frontier.

At his house two notable "council fires" were held with the Indians of the Six Nations and other tribes.

At a conference of Governor Hamilton with them, August 23, 1762, they asked that "the present store-keepers may be removed and honest men placed in their stead," and selected John Harris Jr. Said the chief, who addressed the governor, "I think John Harris is the most suitable man to keep store, for he lives right in the road where our warriors pass, and he is very well known by us all in our Nation, as his father was before him."

Harris's house, built in 1766, along what is now Front Street in downtown Harrisburg, still stands today.