The online operation will have a reduced editorial staff
The Seattle Post-Intelligencer, the 146-year-old US newspaper, will print its final edition on Tuesday before becoming a strictly online operation.
Owner Hearst Corporation has failed in its attempts to find a buyer for the paper, put on sale in January.
America's newspaper industry has been badly hit by the downturn, and a number of titles face closure.
The decision to go solely online is the first such venture for a large US paper.
However, the website will be run solely as a source of local news and opinion, rather than an internet incarnation of the former newspaper.
There will be an editorial staff of 20, compared to the previous 150. The remaining editorial staff will be expected to write, edit, take photos, and shoot video.
"We don't feel like we have to cover everything ourselves," said a statement from Michelle Nicolosi, who will lead the site as executive producer.
"We'll partner for some content; we won't duplicate what the wire is reporting unless we have something unique to offer; we'll continue to showcase the great content from our 150 or so reader bloggers and we'll link to content partners and competitors to create the best mix of news on our front page."
Seattle follows Denver in losing a daily newspaper this year, after the Rocky Mountain news closed.
And in Arizona, Gannett's Tucson Citizen is set to close on Saturday, leaving one newspaper in that city.
Last month the San Francisco Chronicle said it plans to cut a "significant" number of jobs to meet cost-cutting targets, and that if the targets are not met, then the paper could be sold or closed down.
The New York Times is struggling to service debts of some $400m, amid dwindling cash reserves and plunging revenue.
Last year it had to mortgage its gleaming new headquarters (built in 2007 with much fanfare) to bolster its cash flow.
The Tribune Company, which owns the Chicago Tribune, the Los Angeles Times, the Baltimore Sun and many other titles, filed for bankruptcy in December, and although its newspapers remain in publication, the repercussions of the bankruptcy filing are likely to lead to restructuring.
Three other newspaper companies have also filed for bankruptcy in recent months.
They are Star Tribune Holding Corporation (which owns the Minneapolis Star-Tribune), the Journal Register Company (which owns the New Haven Register and a number of other titles in the North East), and Philadelphia Newspapers LLC (which owns Philadelphia's two top newspapers, the Inquirer and the Daily News).
The American newspaper industry has been hit by falling advertising revenue in recent years.