For nearly a century, Alaska has served as mainly a toe-touch state for presidents. Next week, President Obama will change all that.

Obama departs Aug. 31 for what will soon be the most extensive Alaska tour in history by a sitting American president. While one other sitting American president has spent more time in Alaska -- Warren G. Harding -- Obama will travel further by journeying further north while also touching southern parts of the state. (Having government planes and helicopters at one's disposal -- something Harding lacked -- helps.)

In addition to traveling to Anchorage for a State Department-sponsored meeting of Arctic Council policymakers, he will fly over glaciers near Seward, in the southcentral part of the state; visit with fishing operators in Dillingham, on the southwest's Bristol Bay; and meet with residents in Kotzebue, 26 miles north of the Arctic Circle.

While past presidents have visited the state for a variety of reasons -- to inaugurate a railroad terminal or meet with a fellow head of state or do a bit of fishing, for example -- Obama's trip has a single purpose: Make the case for his environmental agenda. His itinerary will allow him to celebrate some of the state's most vibrant ecosystems, including the wild salmon runs in Bristol Bay, and its most imperiled, such as the Arctic.

Michael Brune, executive director of the Sierra Club, noted that not only are towns such as Kotzebue coping with retreating sea ice and coastal erosion linked to climate change, they are pursuing renewable energy projects now in an effort to reduce their reliance on high-priced diesel.

"Alaska is the perfect place to visit to showcase the impact of climate change not just on the environment, but the economy," Brune said in an interview.

[How climate change is hitting Alaska's Arctic villages, hard]

Sen. Lisa Murkowski (R-Alaska) said she welcomed Obama's visit, but hoped he would recognize both the possibilities inherent in her state's changing landscape -- and not just the pitfalls.

"Unfortunately we don’t get a lot of presidents here," she said. "Typically when they come, they come for a refueling stop. It makes it harder for us to have people in the White House who know and understand our issues."

" I do hope he’s willing to keep his eyes and ears out for not for the things that he wants to hear played back to him, but is truly looking at our state for the opportunities it presents, as well as our challenges," Murkowski said in an interview Tuesday.

But what about those other presidents, who set foot in the 49th state at different points over the past 92 years? Here's a look at when they went, what they did, and why:

Warren G. Harding, July 8-23, 1923

Harding made history by becoming  the first president to visit Alaska while in office, and did so in style. The nation's 29th president journeyed by ship from Seattle and made at least nine separate stops in a trip that included a train ride from Seward in the southeast to Fairbanks.

The "Congressional Special" train that carried Harding and his party, which now sits in Fairbanks' Pioneer Park, was part of a celebration of the completion of the Alaska Railroad. Harding drove in a golden spike at Nenana on July 15 with much fanfare; on Aug. 2, he died, while still on his so-called "Voyage of Understanding."

Franklin D. Roosevelt, Aug. 3-9, 1944

As part of trip across the Pacific during World War II, Roosevelt's trip included an inspection and fishing trip. In the course of it, he went to the Southeast, Kodiak and the Aleutians. For those keeping track, Juneau ranked as his most productive fishing spot.

Dwight Eisenhower, June 12, 1960

While Eisenhower is the president who ushered Alaska into statehood, he didn't spend much time there. While en route to Asia, Eisenhower addressed troops at Elmendorf Air Force Base and cruised through Anchorage in a parade.

Recalling that in Kansas it was "synonymous with the gold and glamour of the Yukon and Klondike; the home of sourdoughs and Eskimos ... certainly I can assure you that never for a moment did it enter my head that one day as President of the United States I would urgently recommend statehood for Alaska and later welcome it as a State into our great Union."

Lyndon B. Johnson, Nov. 2-3, 1966

Nursing a sore thumb on his return from Asia, Johnson received an enthusiastic reception from a crowd at midnight when he journeyed from Elmendorf to downtown Anchorage. Later, according to his diary, he complained that the media reported that Robert F. Kennedy was "mobbed" by 200 people while he had gotten a much larger crowd.

"We've got to get some local color on this Alaska arrival," he told his aides over a nightcap in a suite at the Westward Hotel. "At midnight, with 30,000, I don't see why we can't get color. But we won't."

Richard Nixon, Sept. 26, 1971

Nixon's presidency marked several international firsts, and Alaska was no exception. By stopping at Elmendorf Air Force Base and meeting Nixon there, Japanese Emperor Hirohito became the first Japanese emperor to step on foreign soil.

He and Empress Kojun met the president and his wife, Pat, at the base, where they both delivered remarks, and then went to the residence of Lt. Gen. Robert Ruegg before parting ways.

Gerald Ford, Nov. 17, 1974, and Nov. 29, 1975

Ford restricted his two Alaska visits to Air Force bases -- first Elmendorf in Anchorage, and then Eielson in Fairbanks. On his second visit, Ford noted with pride he had visited Alaska "just a little over a year ago on a previous trip" to the Pacific.

"This obviously doesn't make me a 'sourdough,' but I am no newcomer to the knowledge that this great land, a part of another great land, the United States of America, is an inspiring and shining northern star in our constellation of stars," he said.

Jimmy Carter, June 23, 1979, and July 9-11, 1980

Carter's presidency transformed the state's landscape: The Alaska National Interest Lands Conservation Act, which he signed just before leaving office on Dec. 2, 1980, provided federal protection for more than 157 million acres in the state.

But he didn't spend much time there while in office, stopping over twice. The first time, on his way to the Tokyo Economic Summit, he attended a reception at Elmendorf's Officers Club with Alaskan political leaders and citizens. On his second visit -- this time on his return from Japan -- he stayed overnight at the base and then flew by helicopter 121 miles to Clarence Lake to have a five-hour fishing trip with then-Secretary of State Edmund Muskie; Rupe Andrews, director of the Alaska State Division of Sport Fishing; and Alaska Gov. Jay Hammond (R).

Speaking to reporters before he boarded Air Force One for Washington, Carter said that he had "a very delightful and a very successful fishing trip. ... We had a chance to fish for about five hours and to travel about an hour-and-a-half in and back and really thoroughly enjoyed the brief vacation. It reminds us again of the beauty of Alaska and the wonderful gifts that God has given our country, and I'm very grateful for this chance to see part of it."

It is worth noting that during that fishing expedition, Carter, like Harding, set foot on a glacier. Writing later in his book "An Outdoor Journal," he recalled, "We flew northward from Anchorage, circled Mount McKinley, landed on one of the glaciers to see the slowly flowing ice at first hand, and flew close to some cliffs to observe a number of Dall sheep on the steep mountainsides."

Ronald Reagan, Jan. 16, 1983, and May 2-3, 1984

Reagan passed through Elmendorf in 1983  before conducting diplomacy more than a year later in Fairbanks. During that second trip, he welcomed Pope John Paul II  in an outdoor ceremony at Fairbanks International Airport just after returning from China. Reagan told the pope, ''In a violent world, Your Holiness, you have been a minister of peace and love.''

In addition to meeting with the pope for the second time during the stop, Reagan also visited the University of Alaska-Fairbanks and stayed overnight at then-Sen. Frank Murkowski's (R) house.

Bill Clinton, Nov. 11, 1994

Clinton used his brief Alaska appearance as an opportunity to snack. He journeyed downtown with then-Gov. Tony Knowles (D) to grab a sandwich. As they stopped by Downtown Deli -- which Knowles used to own -- Clinton told reporters, "I want you to hear Tony's spiel for reindeer stew."

George W. Bush, Feb. 16, 2002, Nov. 14, 2005, and Aug. 4, 2008

Bush is the only American president to live in Alaska -- for a few months in 1971 -- and as a wartime president, Bush devoted both of his multiple visits to addressing the troops at its two major Air Force bases.

On his first appearance at Elmendorf, referring to the Sept. 11, 2001, terrorist attacks, he said: "It's hard for me to figure out what was going through the minds of those who planned and attacked America. They must have thought we were soft."

"They were wrong!" an audience member cried out.

"Yes, they were," Bush responded.

Obama, Nov. 12, 2009

Obama stayed in Alaska for less than two hours when he refueled here during his first year in office. Still, he told the audience at Elmendorf Air Force Base that he was "really excited because I had up until today visited 49 states, so this is officially my 50th state."

Six years later, he's ready for a repeat.

Correction: An earlier version of this piece misstated the location of Seward, Alaska, and the sponsor of this month's Arctic policy meeting in Anchorage.