Abby Fairgate (formerly Cunningham, Ewing and Sumner) is a fictional character from the CBS prime time 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 Donna Mills between 1980 and 1989. Abby was created by producer David Jacobs as one of Knots Landing's earliest characters. She debuted in the first episode of the second season. Mills remained a principal actor in the series until she left in its tenth season. She returned for the two-part series finale in 1993, and made her last appearance in 1997 when she appeared in the reunion miniseries Knots Landing: Back to the Cul-de-Sac.