State Department spokesman Victoria Nuland said Schmidt and Richardson would be traveling as private citizens, not representatives of the U.S. government.
"Frankly, we don't think the timing of this is particularly helpful," Nuland told reporters, citing North Korea's launch of a long-range rocket in December. "They are well aware of our views."
A source familiar with the matter on Thursday confirmed an Associated Press report that Schmidt planned to visit North Korea with Richardson, a former governor of New Mexico, former U.S. ambassador to the United Nations and diplomatic troubleshooter.
The AP said Schmidt, a top figure in the U.S. technology industry and a key executive at the world's leading search engine company, could visit as early as this month but it said it was unclear who he would meet or what his agenda is.
Google's mission is to organize the world's information and make it universally accessible and useful. North Korea is one of the world's most repressive states, with Internet access limited largely to the most
Nuland stressed Schmidt and Richardson were not acting on behalf of the United States.
"We are obviously aware of the trip that has been announced," she said, later correcting herself to say that the department was aware of media reports about the trip.
"They are private citizens. They are traveling in an unofficial capacity," she said. "They are not going to be accompanied by any U.S. officials. They are not carrying any messages from us. They are private citizens and they are making their own decisions."
On Wednesday, Google did not directly respond to a question about whether Schmidt was going to North Korea, although a spokeswoman's response suggested a visit would not be for company business.
"We do not comment on personal travel," spokeswoman Samantha Smith said on Wednesday when asked about the AP report.
North Korea said its Dec. 12 rocket launch put a weather satellite in orbit but critics say it was aimed at nurturing the kind of technology needed to mount a nuclear warhead on a long-range missile.