Idella Thrasher Sehorn (May 28, 1927 – March 14, 2001), née Idella Thrasher, was an American competition swimmer. Sehorn was born in Portland, Oregon, and she grew up in Oregon City. She began swimming at a young age at the Columbia Athletic Club in Portland. Following World War II, she married her coach, Al Sehorn, and began to set records in her best event, the breaststroke. From 1950 to 1953, she set 18 American records in the event. In 2000, she was diagnosed with lung cancer, and died in Los Altos in 2001.