Members of the Renfrew Detachment of the OPP responded to a call at 2:39 p.m. on Charles St in Arnprior.
An adult female was transported to hospital by paramedics where she died of her injuries.
An adult male has been arrested and is in custody.
Charles St. is closed between Daniel St. S and Isabella St. while police continue their investigation.
The Renfrew County Crime Unit, under the direction of OPP Detective Inspector Rob Hagerman, Criminal Investigation Branch, is continuing the investigation.