Catherine E. Coulson, an actress best known as the enigmatic Log Lady in the TV series “Twin Peaks,” died Sept. 28 at her home in Ashland, Ore. She was 71.

The death was confirmed by an official with the Oregon Shakespeare Festival, where Ms. Coulson appeared in 50 plays during the course of 22 seasons. The cause was cancer.

Ms. Coulson met “Twin Peaks” director David Lynch in the early 1970s at an acting workshop at the American Film Institute in Los Angeles. She also served as assistant director, still photographer and special effects technician on “Eraserhead,” the 1977 film that helped launch Lynch’s career.

In 1990, for “Twin Peaks,” Lynch cast Ms. Coulson as Margaret, a mysterious woman who carries around a log that supposedly reveals secrets about the town and its people.

“I look at the Log Lady as the Margaret Mead of ‘Twin Peaks,’ ” she once told the Boston Globe. “She’s the observer . . . she gives the sense of the undercurrent of what’s going on.”

Catherine Coulson in an undated photo. (Oregon Shakespeare Festival/AP)

She added: “Actually, I’ve grown to love the log. I don’t want to sound too weird but it fills the curve in my arm in a very intimate way.”

Catherine Elizabeth Coulson was born in Ashland on Oct. 22, 1943. She grew up in Southern California, where her mother was a ballet dancer and her father was a radio and television producer who also worked in public relations.

She received a bachelor’s degree in theater from Scripps College in Claremont, Calif., and a master of fine arts degree from San Francisco State University.

Her film and TV credits included “Portlandia,” “Psych,” “The Secret Life of Houses” and “Twin Peaks: Fire Walk with Me.”

Her first marriage, to “Eraserhead” star Jack Nance, ended in divorce. She subsequently married Marc Sirinsky, with whom she had a daughter. Complete information about survivors was not immediately available.