Biff leaves his house.
The Tannen residence at 1809 Mason Street in Hill Valley was the 1955 home to Biff Tannen and his grandmother Gertrude Tannen.
Marty McFly tracked Biff down to this location to gain Grays Sports Almanac.
It was on the opposite side of town from the future Lyon Estates.[1]
Behind the scenes
Interestingly enough, this house is only three houses down from Lorraine's house in real life on Bushnell Street in Pasadena.
The Part II novelization states the address as being 2311 Mason Street.