As he aims for an upset victory in Iowa's Republican presidential caucuses, Florida Gov. Ron DeSantis is fulfilling his goal of stopping in all 99 counties in the state that holds the first contest on the GOP nominating calendar.

DeSantis will make his final stop Saturday in Jasper County, where he'll be joined by popular Iowa Republican Gov. Kim Reynolds, who endorsed him in early November.

Also teaming up with DeSantis will be Bob Vander Plaats, president and CEO of The Family Leader, an influential social conservative organization in a state where evangelical voters play an outsized role in Republican politics. Vander Plaats endorsed DeSantis two weeks ago.

"We’re going to win here. We have what it takes," DeSantis pledged in a recent Fox News Digital interview in Des Moines, Iowa.

GAME ON IN IOWA WITH THE CAUCUSES CLOSING IN 

Iowa Governor Kim Reynolds Endorses GOP Candidate Ron DeSantis For President

Florida Gov. Ron DeSantis, a Republican presidential candidate, speaks with Iowa Gov. Kim Reynolds during a campaign rally Nov. 6, 2023, in Des Moines, Iowa. Reynolds endorsed DeSantis' run for president at the event.  (Scott Olson/Getty Images)

As part of that push, DeSantis is completing what's known as "the full Grassley," named after Sen. Chuck Grassley of Iowa. The longtime Republican senator pioneered the all-county tour and has been doing it more than four decades.

"We're going to complete the full Grassley. That'll be 99 counties," DeSantis told reporters Thursday. "We're very excited about doing that. I think you have to do it to win Iowa. I think that's what voters want to see. I think they want to be able to meet you."

THIS CANDIDATE REMAINS IN THE DRIVER'S SEAT AS THE FIRST VOTES IN THE GOP PRESIDENTIAL RACE NEAR

And he pledged that "the fact that we did it doesn't mean we're not going to hit a lot more counties, again, over between now and caucus night."

DeSantis is hoping to follow in the footsteps of former Arkansas Gov. Mike Huckabee (2008), former Pennsylvania Sen. Rick Santorum (2012) and Texas Sen. Ted Cruz (2016), who stopped in all 99 counties en route to Iowa caucus victories.

But none of those three won the GOP nomination.

DeSantis, Ramaswamy, and Haley share personal stories at Iowa evangelical forum

Republican presidential candidates (from left to right) Florida Gov. Ron DeSantis, biotech entrepreneur Vivek Ramaswamy and former Ambassador to the United Nations and former South Carolina Gov. Nikki Haley join The Family Leader president and CEO Bob Vander Plaats (right) at a candidate forum in Des Moines, Iowa, Nov. 17, 2023 (Fox News/Paul Steinhauser)

Pointing to the Reynolds and Vander Plaats endorsements and backing from plenty of other politicians in Iowa, DeSantis argued his campaign is "in better shape by far than previous caucus winners. And so we're going to continue to take that momentum all the way to caucus night for victory."

Longtime Republican strategist David Kochel, a veteran of numerous presidential and statewide campaigns in Iowa, told Fox News that pulling a "full Grassley" is "kind of an inefficient use of candidate time because 70% of Iowans live in 30 counties. But it is a good messaging point, and it is a way to demonstrate that you’re committed to the process."

"It’s a way to say, ‘I respect the Iowa caucus process. I’m going to do it the right way, and I’m going to go everywhere and earn your vote,'" Kochel said.

The Florida governor will be the second Republican White House hopeful this cycle to stop in all 99 counties, following long shot candidate Ryan Blinkley, a little-known pastor and entrepreneur from Texas who accomplished his quest in early November.

DeSantis is battling Nikki Haley, the former ambassador to the United Nations and former South Carolina governor, for second place in the latest GOP presidential nomination polls in Iowa, far behind former President Donald Trump. The former president remains the commanding Republican frontrunner in Iowa, the other early voting states and in national surveys as he makes his third straight bid for the White House.

Former President Donald Trump in IowA

Republican presidential candidate and former President Donald Trump speaks during a rally Nov. 18, 2023, in Fort Dodge, Iowa. (AP Photo/Bryon Houlgrave)

Trump also returns to Iowa Saturday to hold caucus organizing events. And his campaign is ramping up its ad buys in the state the final weeks ahead of the caucuses.

While Trump has hosted nearly 20 events in Iowa this year, the Florida governor has made roughly 130 stops, many of them hosted by the DeSantis-aligned super PAC Never Back Down. Additionally, the super PAC has spent millions to put together a formidable ground game in Iowa.

However, what once appeared to be a two-candidate fight for the nomination is now a three-way battle.

Haley, who has enjoyed momentum in the polls in recent months, thanks in part to well-received performances in the first three GOP presidential primary debates, has leapfrogged DeSantis for second place in New Hampshire, which holds the first primary and votes second in the Republican nominating schedule, and her home state, which holds the first southern contest.

She aims to make a fight of it in Iowa, where she is pulling even with DeSantis in some of the latest polls.

"The momentum is real. The excitement is there. We’re going to keep working hard to win every Iowan’s vote. We’re not going to give up on Iowa," Haley said in a Fox News Digital interview ahead of a recent town hall in Newton, Iowa.

Haley recently showcased over 70 new Hawkeye State endorsements and on Friday launched a $10 million ad blitz in Iowa and New Hampshire.

She also landed the backing earlier this week of Americans for Prosperity Action, the political wing of the influential and deep-pocketed fiscally conservative network founded by the billionaire Koch Brothers. AFP Action has pledged to spend tens of millions of dollars and mobilize its formidable grassroots operation to boost Haley and help push the Republican Party past Trump.

Pointing to DeSantis, Haley and Trump, Kochel said "it feels to me like everybody understands how determinative Iowa might be in setting this field up for a big dynamic change."

There are also other long shots vying for the GOP nomination campaigning in Iowa.

Multimillionaire biotech entrepreneur and first-time candidate Vivek Ramaswamy is basing his campaign in Iowa for the final stretch as he barnstorms the state. 

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North Dakota Gov. Doug Burgum, who failed to make the stage at the third GOP presidential primary debate, is also spending plenty of time in Iowa.

And former Arkansas Gov. Asa Hutchinson, who sits at less than 1% in the polls and who has missed the past two debates, also remains in the race and is campaigning in the Hawkeye State.

Former New Jersey Gov. Chris Christie, who is running for the White House a second time, is avoiding Iowa as he once again concentrates much of his firepower in New Hampshire, where he has double-digit support.

"Right now, people are starting to make up their minds," Kochel said with just over six weeks to go until the caucuses. "They’ve had their top three or top four for a while. Now this thing is really coming down to, ‘Do we stick with Trump or which one of these Trump alternatives deserves to go on with some momentum?’"

Get the latest updates from the 2024 campaign trail, exclusive interviews and more at our Fox News Digital election hub.