I also found what the previous posting said. I think Mildred's parents lived in Sawyer ND. On the 1930 census she states that her mother was born in Penn. and father in Id.
On the 1920 census I found a Mildred agte 12 in Sawyer with father, Parry W Johnson and mother Margreth,born in Penn.
Her father's state of birth is different. Minn. but in 1930 when Mildred was living away from home as a lodger, she perhaps was wrong on her father's birthplace.

She had a brother age 13 on the 1930 census, Robert R Johnson.