Buena Vista Township Fire units responded to a house fire in the 800 block of South 23rd near Hartsuff just after 1:45 Sunday morning.  They called for mutual aid from the Saginaw Fire Department.  Firefighters confined most of the flames to one room of the home.  Authorities say a woman died as a result of the fire.  The victims name has not been released.  The cause of the fire is under investigation.