We put a call out to listeners and none of the explanations checked out so we took the question to the East Benton County Historical Society Museum. Here’s what they said:

 

“This is one of the most-asked question here at the museum. I’m sending you the information from our publication, ‘Benton County Places & Names.’”

 

Unfortunately, the excerpt from the publication didn’t actually answer the question of WHY.

“Several tales ending with, ‘Jump off Joe, Joe’ suggest a source of the name but ‘facts’ in each of them are easily disproved. To the earliest settlers the name was simply Jump Off Joe.”

 

Apparently efforts were made to name it something different, to the consternation of locals! More from the article:

“The highest hill south of Kennewick (2,196 ft.) bristling with antennas and communication equipment. The earliest such use was in 1926 when signal lights were placed there to guide the first airmail planes. In 1964, government mapmakers marked the name Communication Hill on the maps but old timers objected and the name was dropped.”