The Great American Outdoor Show's brought tens of millions of tourism dollars to the Capitol region for 25 years.
It's also sponsored by the NRA.
This February, Harrisburg Mayor Eric Papenfuse says police won't provide security inside the Farm Show Complex, as is customary.
Papenfuse says his decision is tied to the NRA's support of the state law that made it easier to sue Pennsylvania cities over their firearms ordinances.
"It's no secret that the NRA has worked against the city's interests repeatedly over the past year, causing us to spend tens of thousands of dollars to defend common sense gun ordinances," Papenfuse said.
Pennsylvania's Act 192 was short-lived, overturned last fall within 10 months of its effective date.
But it prompted about 100 municipalities to repeal their gun ordinances, in an effort to reduce their exposure to lawsuits. Some of those that didn't were sued, including Lower Merion Township and the cities of Philadelphia, Lancaster, Pittsburgh and Harrisburg.