Maybe, as Kenneth Davis suggests, it started when the corner gas station stopped giving away road maps. Or when we realized that the phys ed coach didn't want to teach that geography class any more than we wanted to take it. Or when Bob Hope filmed his last "The Road to . . . " movie.
But sometime in the 20th Century, Americans lost the natural fascination and joy small children get from spinning a globe and stopping it with their fingertips to see what exotic daydream a turn on the axis might deliver.
This was the underlying message of a 1988 Gallup survey, commissioned by the National Geographic Society, that put the term geographic illiteracy on the map.
The survey found that 75% of Americans aged 18-24 couldn't locate the Persian Gulf on a world map; 25% couldn't find the Pacific Ocean; and one in seven couldn't point out the United States.
That was four years ago. Yet, other than a war that focused American attention on the Persian Gulf for a short time, little evidence suggests Americans now are any more likely to know the Grand Tetons from the Grand Canyon.
"This problem of geographic illiteracy cuts across all ages and really is an American problem," says Davis, a studious New Yorker whose own flair for spinning stories on this down-to-earth subject translated this year into the best-selling "Don't Know Much About Geography" (Morrow, $23).
Davis believes there are reasons Americans confuse the points on a compass. "We were discovered by this lost sailor who thought he was in China," he says, joking, "and it's been downhill since then."
But seriously, Davis believes the roots of our geographic ignorance actually are historic.
"For a nation of people who primarily arrived by boats, we all turned our backs on the ocean," he says. "We had this big country that seemed like it was wide enough and big enough and had enough resources to last us forever.
"So I think it's part of the American character. Or maybe it's the fortress idea that we have these big oceans to protect us against Europe's messy little affairs . . . but that doesn't explain why we can't identify Canada and Mexico. And why South America is a total blur for most Americans."
Davis also blames topographic fumbling on textbooks that treat geography as a cardboard subject without multiple dimensions, without a sense of humanity.
"Textbooks are really horrific," he says, explaining that they're written not for the imaginative minds of youngsters but for 50-year-old school administrators who approve their purchase for classrooms.
"In geography texts, you have places presented with no sense of their unique character, or what it is that makes them interesting. History, the environment, literature, religion, language--all of these things have a geographic basis and you have to constantly show those connections."
Davis is encouraged, however, that more Americans now recognize the geography problem not only as an embarrassing educational lapse but as a detriment to our success in a global economy. He's seen promising indications.
CNN broadcasts use the words international and overseas because foreign is a pejorative for many Americans. And he recently visited a high school program in Detroit, called the Center for International Studies, where students learn two languages (one Asian) and develop relationships with cities in Europe and Asia.
"People are not ignorant for lack of interest," he says.
"They are not ill-informed because they don't care. There are a lot of folks out there who get National Geographic and watch the National Geographic shows on PBS. They just want their geography in a format that's a little more appetizing. And there's nothing wrong with that."