I just learned of this recently on a show about Alaska. I never heard anything about it in any history class. I've asked my friends and the vast majority had never heard of it either. As the only WW2 battle fought on American soil why is this so often glossed over or ignored?
Why was it ignored? The Aleutians campaign was a sideshow in WWII. The outcome of the fighting there would never have decided the outcome of the war for either side.
Normandy, Okinawa, and Midway all mattered far more when it came to deciding the course of the war and so they receive more attention in popular memory.
From the afterword of The Thousand-Mile War by Brian Garfield:
Was it the presumed strategic insignificance of the Alaska-Aleutian theater that made it a topic of commensurate insignificance to most writers and publishers? I think there is more to it than that.
When I was digging in the National Archives and the Pentagon's records, I saw that it was mainly after the fact that the importance of the North Pacific theater was downgraded. During the war itself there were times when the theater actually was regarded by high-ranking planners on both sides as having more strategic significance than is justified in hindsight by the realities of the day.
At times during the war no one could be certain whether the Alaska theater was vitally important. When one mixed in such factors as Lend-Lease and the American effort to seduce the Russians into declaring war on Japan, the unimportance of the theater became quite a lot less absolute. At the strategic level, uncertainty and embarrassment and paranoia all may have contributed strongly to the Alaska war's being kept under wraps.
Also, by coincidence, most of the dramatic moments of the Alaska war happened to be eclipsed in public perception by momentous events elsewhere—Midway, North Africa, Crete, Sicily, Guadalcanal, so forth.
Still, if the home fronts in America and Japan remained largely unaware of what was going on in the North Pacific, it was because both governments imposed intense blackouts on news from the Alaska theater. During most of the campaign, neither side allowed journalists anywhere near the battlefronts. Those few who did write from vantage points near ground zero (Corey Ford, Dashiell Hammett, et al.) found their dispatches gutted by censorship so heavy-handed and pervasive that I still had to battle it strenuously many years later when I was trying to learn about the campaign. R is instructive to observe that the Aleutians campaign received more coverage in National Geographic Magazine (whose mostly free-lance photographers and reporters were disregarded by the government as insignificant naturalists) than it did in any newspaper.
I'll also add that the number of soldiers involved in the campaign was relatively small, and the campaign was a dead-end for wartime purposes. Planned airfields for the bombing of Japan were never built, thanks to the advance into the Marianas. In those islands, the weather was good, and flying safer.