Chautauqua County recorded its single-day, largest increase in new cases of COVID-19.

The county Health Department reported 90 new cases on Friday, beating the previous single-day record of 57 new cases reported in November.

Of the new cases, 23 involve people living in the Jamestown zip code, 12 in Fredonia, eight in Dunkirk, 14 in Mayville, nine in Lakewood and four each in Ripley and Bemus Point. Several municipalities have one or two cases as well.

The number of active cases increased as well, from 199 on Thursday to 263 on Friday.

The source of the new cases wasn’t immediately clear; dozens of inmates and staff at the Chautauqua County Jail tested positive for COVID-19 following an outbreak. The county also held a rapid testing site this week.

County Executive PJ Wendel warned that gatherings during the Thanksgiving holiday would likely result in more cases being reported.