Hennessey is a town in Kingfisher County, Oklahoma, United States. The population was 2,058 at the 2000 census.
Hennessey is named after Pat Hennessy, an Irish freighter who was killed at the present townsite in April, 1874. He was said to have been burned on a wagon wheel, either by native Cheyenne tribesmen or white horse thieves.
The Pat Hennessey Memorial Park can be found at the streets of Iowa and Arapaho. The location of his body is another story. Pat Hennessey was originally buried next to the location of his death in a shallow grave. Rocks were placed over his body, and teamsters passing by would continue to place markers on his grave. At some point in history Pat’s body was moved. It is possible Pat’s relatives came from Ireland and reclaimed his body. In any case, it is not at the marker site at Memorial Park: excavations there produced no remains.