Public Health reports four new cases of COVID-19 on Tuesday, bringing the total of active cases to 26.
The increase comes after a recent outbreak at Linhaven nursing home in St Catharines, which saw three additional cases reported among staff over the weekend.
There was no immediate information about where Tuesday's cases were found.
Close contact with an already existing case remains the biggest source of infection, according to regional figures, followed by community transmission.
A total of 783 cases of COVID-19 have been found in Niagara since March 13.
64 people have succumbed to the infection.
