The health department reports more than 2,700 hospitalizations from 57 counties.
So far, a total of 1,900 people have been hospitalized from 50 counties. But officials don't expect the numbers to rise much more.
A hospital in Grand Junction is asking sick people not to visit patients.
Ninety-five people from 17 Colorado counties have been hospitalized due to flu.
Flu-related hospitalizations are "the tip of the iceberg" said the state epidemiologist.
The number of flu cases has risen dramatically in Colorado in the past two weeks.