That is also the highest level of claims since July 1992, the department said, when the U.S. economy was coming out of a recession.
The four-week average of claims, which smooths out fluctuations, was even worse: it rose to 506,500, the highest in more than 25 years.
In addition, the number of people continuing to claim unemployment insurance rose sharply for the third straight week to more than 4 million, the highest since December 1982, when the economy was in a painful recession.
Those figures partly reflect growth in the labor force, which has increased by about half since the early 1980s. The percentage of workers who receive unemployment benefits - which is different from the unemployment rate - increased to 3 percent, the highest since June 2003. Less than half of unemployed workers receive unemployment insurance.
The figures likely will cause some economists to increase their projections for the unemployment rate this year. Many already expect unemployment to reach 7 percent by early next year and 8 percent by the end of 2009.
The rate in October was 6.5 percent, and last year the rate averaged 4.6 percent.
The Federal Reserve on Wednesday released projections that the jobless rate will climb to between 7.1 percent and 7.6 percent next year, according to documents from the Fed's Oct. 29 closed-door deliberations on interest rate policy.
Initial claims have been driven higher in the past several months by a slowing economy hit by the financial crisis, and cutbacks in consumer and business spending.
Economists consider jobless claims a timely, if volatile, indication of how rapidly companies are laying off workers. Employees who quit or are fired for cause are not eligible for benefits.
Several companies announced mass layoffs in the past week, including Citigroup Inc., Union Pacific Corp. and Sun Microsystems Inc.