MANSFIELD -- Richland County remained the only "red" county in north central Ohio, Gov. Mike DeWine announced Thursday afternoon in updating the Public Health Advisory System.
A total of 23 of the state's 88 counties, or 26 percent, are now designated "red," or level three, up from 19 last week.
Ashland and Crawford counties remained "yellow," or level one, on Thursday while Knox County moved into "orange," or level two.
The public health advisory system is based on seven "indicators" that reflect the spread of the virus. Level three is reached when a county triggers 4-5 of the above indicators.
There are no "purple," or level four counties in the state. A statewide mandate to wear masks in public begins Thursday at 6 p.m., an order DeWine announced Wednesday.
Prior to that announcement, only residents in "red" counties were ordered to wear masks in public.
Richland County, which reported its ninth COVID-19 death on Thursday, had been "orange" on July 2 and July 9 before being designated "red" on July 16.
The level three designation means there is "very high exposure and spread of COVID-19 in Richland County. Residents are encouraged to limit activities as much as possible and to follow all current health orders."
This includes when in any indoor location that is not a residence; outdoors when unable to consistently maintain a distance of six feet or more from individuals who are not members of their household; waiting for, riding, driving or operating public transportation, a taxi, a private car service or ride sharing vehicle.
According to the ODH, Richland County triggered the same four indicators this week that it did last week: new cases per capita; proportion of cases not found in congregate situations; sustained increase in emergency room visits and sustained increase in outpatient visits.
ODH said Richland County has had 78 total cases in the past 14 days, representing 19 percent of the county's total cases since the pandemic began in March.
Counties upgraded to level three this week are Clark, Defiance, Erie, Hardin, Henry, Lawrence, Maron and Medina.
Four counties were downgraded to orange from red -- Butler, Lorain, Summit and Wood.