Take a look at a map of the Arctic with the North Pole dead center. There sure is a lot of blue sea and not all that much land.

Given what we know now, Peary’s claim about Crocker Land might seem disingenuous. And maybe it was. However, the word of this man was taken seriously enough to have inspired an entire expedition with the primarily goal of seeing if he was right, and other Arctic explorers also sought it. There are several reasons why Crocker Land seemed plausible in the early 1900s.
What Greek Myth, Frankenstein, and Inuit Lore Share
First, the promise of land in the far north is an old, old idea. The ancient Greeks wrote of Hyperboria, a land beyond Boreas, the north wind. The sun never set on this polar paradise, where the Hyperborians lived happily with thousand-year lifespans. The lifespan of the myth was even longer, surviving in literature — including, oddly enough, Mary Shelley’s 1818 novel Frankenstein. That’s where sea captain Robert Walton, the frame narrator, writes this in a letter to his sister:
I try in vain to be persuaded that the pole is the seat of frost and desolation; it ever presents itself to my imagination as the region of beauty and delight. There, Margaret, the sun is for ever visible, its broad disk just skirting the horizon and diffusing a perpetual splendour. There—for with your leave, my sister, I will put some trust in preceding navigators—there snow and frost are banished; and, sailing over a calm sea, we may be wafted to a land surpassing in wonders and in beauty every region hitherto discovered on the habitable globe.
It certainly wasn’t empirical science, but the centuries of legendary land at or near the North Pole set the stage for anticipating actual land there.
Something similar, if less paradisaical, appears to have existed in Inuit lore, too. The best article I’ve found addressing this is titled “An Undiscovered Island Off the Northern Coast of Alaska,” published in an 1893 issue the National Geographic. The second section of this piece spotlights a tale told by the indigenous people of Point Barrow, the uppermost tip of Alaska. Captain Edward Peery Herendeen explains that the story is set in the hazy “long ago” and proceeds to paraphrase it:
An Eskimo was out on a whale hunt with his umiak and crew (in April or May). Venturing much farther than their companions and being encompassed by ice, they were carried away to the north and east by the moving pack until at last they came in sight of a strange land. After many hardships and the death of most of the crew, some at last reached the mainland, their own beloved 'Nunah' greatly exhausted, and related their adventures to wondering listeners.
Herendeen interprets this to be testimony of, not a legend about, actual “land somewhere to the north and east of point Barrow.”
The Precedent of Captain Keenan
The same article includes discussion of land observed by Captain John Keenan, a whaler from Troy, New York. In the 1870s, Keenan was scouting for whales in the Arctic when land was “distinctly seen.” More concerned with profit, the captain followed the herd rather than investigate that island.

I’m having trouble finding good primary evidence about Keenan’s experience — it all seems to be secondhand, long-after-the-fact stuff. For instance, I’m not able to find the original online, but The ExploreNorth site transcribes a 1910 obituary for Keenan that wildly contradicts Heredeen’s description of the Captain simply spotting land and sailing on. Instead, it offers a much grander version of the event, complete with a safe landing from a storm, a US flag planted, and official recognition from Washington, D.C. Something like Hyperboria, it seems Keenan and the so-called “Keenan Land” grew into legend, yet readers might have been convinced that his finding Arctic land served as a precedent for Crocker Land.
Along with Kennan Land were similar cases, notably, Sannikov’s Land. In an article titled “Some Problems of Polar Geography,” R.N. Rodmose Brown touches on these and other examples.
Speculations of a Scientist (Map Included)
That conviction was reinforced by a theory put forth by Dr. Rollin A. Harris, who worked for the Coast and Geodetic Survey. Harris first published his theory in a 1904 article titled “Some Indications of Land in the Vicinity of the North Pole.” Sort of an armchair explorer, he explains that reports of sea currents made on various voyages dating back to the 1850s, when combined, point to “a large tract of land dividing the deep Arctic channel.” Harris goes on to say, “That land probably extends to the north of Beaufort Sea can be inferred from the fact that the ice found here is very old, the sea seeming to have no broad outlet through which the ice can escape, as it does north of Siberia.” To currents and old ice, he adds tides. Concluding with reports of land made by Inuit and other seafarers, he offers this map with his hypothetical land mass marked by horizontal lines:

Harris’s 1904 map still appeared in prominent newspapers at least as late as 1925. This is the year Donald MacMillan launched an Arctic expedition with the advantage of aircraft after coming back empty-handed from the 1913 Crocker Land Expedition.
The Antarctica Parallel
Yet another reason why Crocker Land might’ve felt plausible in 1907 is what was then known about Antarctica. Though confirmation of Antarctic land began in the 1820s, the 1890s saw a small parade of Norwegian, Belgian, and British expeditions departing to explore the continent. In the first decade of the 1900s, Scott and Shackleton were joined by explorers from Germany, Sweden, and France. If there was a continent at the South Pole, why not one at the North Pole?
Tellingly, those referring to undiscovered land in the Arctic sometimes referred to it — not as an island or even an archipelago — but as a continent. Forgive the pun, but that’s quite a broad assumption, given that the Arctic was pretty familiar territory by the early 1900s. A good example of this language appeared a year before Peary announced his sighting of Crocker Land. Ejnar Mikkelsen was preparing an expedition intending, in part, to seek undiscovered land. At least one news report builds anticipation for a profound revelation with the headline: “A POLAR CONTINENT.” In the article, Alfred Whitehouse borrows from Harris by describing “a vast unknown Polar continent or archipelago, which, from soundings, driftwood, thickness of ice, currents, etc., is thought to exist in the Beaufort Sea north of the American continent.”

Disappointingly, in Conquering the Arctic Ice (1909), Mikkelsen reports this expedition “proved deep water” where Captain Keenan and his crew “claimed to have seen land.” Amusingly, newspapers continued to sensationalize the prospect of a hidden continent near the North Pole, and this article in a 1922 issue of the Washington Times — with its visions of dinosaurs, ape-men, and ancient ruins — seems less rooted in fact and more influenced by Arthur Conan Doyle’s novel The Lost World of a decade earlier. Nonetheless, did this talk of an entire continent at the northern tip of the world result from verification that there was an entire continent at its southern tip?
Plausibly.