Ed. Note: The Republican Party of Iowa held an informational meeting at party headquarters on the morning of May 28, 2015.  According to the Des Moines Register, representatives of Carson, Christie, Cruz, Fiorina, Graham, Perry and Trump attended.  See: Jennifer Jacobs.  "Straw Poll meeting offers clues on who will participate." Des Moines Register, May 28, 2015.  Jacobs described the Straw Poll as "beleaguered."  The next day this letter from Republican leaders ran on the Register's Opinion page:

As of June 1 signed by representatives of 94 counties.

May 29, 2015

Dear candidates and potential candidates,
As some of the most active and engaged Republicans in Iowa, we are writing to urge you to participate in the Iowa Straw Poll.
The Straw Poll is a political tradition stretching back to 1979. Many of us remember attending as children, or bringing our own children along while we participated in this grassroots event. In the past, the Straw Poll has drawn more than 20,000 caucus-going Iowa activists, which would make it the largest political gathering in the country. It’s an incredible opportunity for us to meet the men and women running for president, but also an opportunity for you to meet a significant portion of eventual caucus attendees.
While in the past there have been allegations of “pay to play” at the event, the Republican Party of Iowa has taken the necessary steps to update and improve the event. Now the only cost you must incur to participate is the plane ticket to Iowa.
Recently you might have seen some odd accusations leveled at the Straw Poll. Some say it’s an “establishment” ploy, while others say it’s an event dominated by only the most conservative. Neither accusation is accurate: The Iowa Straw Poll is a grassroots event beloved and revered by Iowa Republicans across the political spectrum. All who participate have a fair chance at victory. 
The Iowa Straw Poll is a tradition worth supporting and one grassroots activists will fight to preserve. Fortune favors the bold. We will be in Boone on August 8th and hope to see you there as well.
-Signed by representatives from 92 out of 99 County Parties, totaling 156 chairs and co-chairs.

Adair Chair Ryan Frederick
Adair Co-Chair Bubba Sorensen
Adams Chair Alec Turner
Adams Co-Chair Hank Sorenson
Appanoose Chair Lyle Brinegar
Appanoose Co-Chair Richard Taylor
Audubon Chair Peggy Toft
Benton Chair Tim Busch
Benton Co-Chair Bethany Gates
Black Hawk Chair Scott Atkins
Black Hawk Co-Chair Greg Tagtow
Boone Chair Gary Nystrom
Boone Co-Chair Kay Rice
Bremer Chair Wes Gade
Bremer Co-Chair Matthew Schneider
Buchanan Chair Richard Wearmouth
Buchanan Co-Chair Mandy Crane
Buena Vista Chair Randy Ericksen
Buena Vista Co-Chair Dennis Weber
Butler Co-Chair Ella Severs
Calhoun Co-Chair Mike Sexton
Carroll Chair Craig Williams
Carroll Co-Chair Jean Ludwig
Cedar Chair Velma Huebner
Cedar Co-Chair Sally Miller
Cedar Co-Chair Allen Kroeger
Cerro Gordo Chair Barbara Hovland
Cherokee Co-Chair Mark Leeds
Cherokee Chair Todd Bevard
Chickasaw Chair Nancy Josephson
Clarke Chair Ray Negley
Clarke Co-Chair Dale Mastrarone
Clay Chair Will Jones
Clinton Chair Dan Smicker
Crawford Chair Gwen Ecklund
Crawford Co-Chair Roger Sailer
Dallas Chair Tyler DeHaan
Dallas Co-Chair John Strathman
Davis Co-Chair Tim Batterson
Decatur Chair Bob Bixby
Delaware Chair Jeff Madlom
Des Moines Chair B.J. Jahn
Des Moines Co-Chair Terry Davis
Dickinson Co-Chair David Rowley
Dickinson Chair Mike Koenecke
Dubuque Chair Jennifer Smith
Dubuque Co-Chair Monty Alexander
Emmet Co-Chair Kim Hageman
Emmet Chair John Brickner
Fayette Chair Rick Hofmeyer
Fayette Co-Chair Larry Clipperton
Floyd Chair Charley Thomson
Franklin Co-Chair Tom Crane
Fremont Chair Freddie Krewson
Grundy Chair Brian Andersen
Guthrie Chair Dean Hopkins
Guthrie Co-Chair Myrna Beeber
Becky Kepler
Rick Young
Hancock Chair John Walker
Hardin Chair Rick Brockmeyer
Harrison Chair Wayne Bahr
Harrison Co-Chair Chuck Petterson
Henry Chair Bruce Weber
Henry Co-Chair Troy Eichelberger
Howard Co-Chair Kevin Schoeberl
Ida Chair Mary Clark
Ida Co-Chair Teresa Paulsrud
Jackson Chair Terry Creegan
Jackson Co-Chair Darlene Block
Jackson Co-Chair Monica McHugh
Jasper Chair Marshall Critchfield
Jefferson Chair Jeff Shipley
Jefferson Co-Chair Marshan Roth
Johnson Chair Bill Keettel
Johnson Co-Chair Mike Kavanaugh
Jones Chair Gerald Retzlaff
Jones Co-Chair Diana Stadtmueller
Jones Co-Chair Lori Dohrmann
Keokuk Chair Tanya Webster
Kossuth Co-Chair Ken Clark
Lee Chair Terry Schrepfer
Lee Co-Chair Larry Kruse
Linn Chair Cindy Golding
Linn Co-Chair Brett Mason
Louisa Chair Angie Davidson
Louisa Co-Chair Lori Irons
Lucas Chair Paul Goldsmith
Lyon Co-Chair John Fluit
Lyon Chair Josh Bakker
Madison Chair Joe Van Ginkel
Madison Co-Chair Heather Stancil
Mahaska Co-Chair Don Polk
Marion Chair T. Waldmann-Williams
Marion Co-Chair Ed Bull
Marshall Chair Peter Rogers
Marshall Co-Chair Shari Coughenour
Mills Chair John Yates
Mills Co-Chair Sharon McNutt
Mitchell Chair Lowell Tesch
Mitchell Co-Chair Tony Krebsbach
Monona Co-Chair Tammy Bramley
Monroe Chair Brad Stalzer
Montgomery Chair Josh Wiig
Montgomery Co-chair Margaret Stoldorf
Muscatine Chair Fred Grunder
Muscatine Co-Chair Ben Janowski
O`Brien Chair Kelly O'Brien
O`Brien Co-Chair Harlan VanderGriend
Osceola Co-Chair Tom Zylstra
Osceola Chair Mary Beltman
Page Chair Dr. John Bowery
Page Co-Chair John Christensen
Palo Alto Chair Jesse Wolfe
Plymouth Chair Don Kass
Pocahontas Chair Michael Ryan
Pocahontas Co-Chair Norma Halverson
Polk Chair Will Rogers
Polk Co-Chair Sherill Whisenand
Pottawattamie Chair Jeff Jorgensen
Pottawattamie Co-Chair Jan Tatum
Poweshiek Chair Nancy Weaver
Ringgold Chair Debra Larson
Ringgold Co-Chair Paul Dykstra
Sac Chair Chris Mason
Scott Chair Judy Davidson
Scott Vice Chair John Ortega
Scott Vice Chair Pat Siemsen
Scott Vice Chair Carol Crain
Shelby Chair Larry Madson
Sioux Chair Mark Lundberg
Story Chair Brett Barker
Story Co-Chair Jeff Ortiz
Tama Chair Brian Oliver
Tama Co-Chair Al Schafbuch
Taylor Chair Stan Mattes
Union Chair Joe Owens
Union Co-Chair Laura Hartman
Van Buren Chair Larry Wagner
Wapello Chair Trudy Caviness
Warren Chair Rick Halvorsen
Warren Co-Chair Steve Armstrong
Washington Chair James Graham
Washington Co-Chair Steve Swaffer
Wayne Chair David Wampler
Wayne Co-Chair Claude Neill
Webster Chair Jim Oberhelman
Webster Co-Chair Karen Glaser
Winnebago Chair Julie Kvale
Winnebago Co-Chair Tom Kuhn
Woodbury Chair Kevin Alons
Woodbury Co-Chair (City) Robert Stewart
Woodbury Co-Chair (County) Michael Clayton
Worth Chair Jeff Gorball
Worth Co-Chair Dave Irons
Wright Chair Larry McBain