Cathy Geary Rush is a fictional character from the CBS soap opera Knots Landing, a long-running serial about middle class life on the fictional cul-de-sac known as Seaview Circle in Los Angeles, California. She was played by actress and singer Lisa Hartman Black between 1983 and 1986. She debuted in the seventh episode of the fifth season. Hartman remained in the series until the final episode of the seventh season. Hartman previously played another character, Ciji Dunne, during the fourth season.