A public health unit is a local or regional organization that delivers public health programs and services to communities. In Ontario, public health units are governed by boards that include municipal representatives and funded jointly by the province and municipalities. Other provinces organize public health through regional health authorities or other structures. Public health units handle disease prevention, health promotion, food safety inspections, immunization programs, sexual health services, and emergency preparedness. They work closely with municipalities on issues like water quality, safe housing, and healthy communities. Public health units played central roles in COVID-19 response, conducting contact tracing, testing, and vaccination campaigns.