Web surfers paid 39.3 million unique visits to newspaper websites in October - a figure which translates to one in four of those using the internet in the United States, according to Nielsen/Netratings, which studies internet usage.
The company on Tuesday found that the New York Times has the most popular newspaper website, drawing 11.4 million unique hits, ahead of US Today, the Washington Post and the Los Angeles Times.
The 11% year-on-year rise in October in online readership confirms growing signs that the future of the newspaper industry is increasingly on the web.
Some 71% of all readers still prefer their daily paper on paper, according to the Nielsen survey.
But circulation figures released last week raised the prospect of a dark future for traditional American newspapers.
The Audit Bureau of Circulations found a 2.6% drop in circulation for 786 newspapers across the country in the six months to September - meaning that 1.2 million people deserted their daily paper.
Executives at a World Association of Newspapers meeting in Madrid were meanwhile told last Thursday that traditional newspapers had no future without online editions.