The following events occurred in the 1970s:
- Unknown dates[note 1] –
- c. 1972 – Ilsa Lindstrom discovers her husband Marty's double life and daughter Annie. Marty leaves Twin Peaks and moves in with Vivian Smith in Yakima, even though Ilsa refuses to grant a divorce.
- c. 1978 – On her deathbed, Ilsa reveals Marty's affair to her daughter Norma, who seeks out and takes a protective interest in her half-sister.
- c. 1979 –