Northville Public Schools said that there have been a few probable or confirmed cases of COVID-19 linked to parties outside of school.
The district sent a letter to parents saying that the parties have resulted in a large and growing number of students who are quarantined.
During contact tracing, the district found that the homecoming parties, and a party bus, were linked to the cases. Those parties, the district said, reportedly had "little evidence of mask wearing and physical distancing."
The contact tracing also found that students who were supposed to be quarantining due to family exposure still participated in out-of-school activities.
So far, two positive cases have resulted in more than 75 students quarantined, which has impacted students at Northville High School and siblings at the middle and elementary schools.
"We are all mightily tired of dealing with this virus, and the impact that it has had on our children, our families and each other. We are seeing the impact of letting down our guard," Superintendent Mary Kay Gallagher said in the letter. "As hard as it is, we urge everyone to give careful thought to working together as families, and as a community to avoid gatherings and other indoor activities that increase the spread of COVID-19, and to continue to seek ways in which we can safely navigate the coming months in a manner that protects everyone’s health and well-being, and keeps our students in school."