Dan Callaghan died in Portland, Oregon on April 13, 2006 from heart disease, Dan was born to John Henry Callaghan and Margaret Laidlaw Callaghan on October 4, 1931, in Salem, Oregon, where he lived his entire life, He graduated from Salem High School and attended the University of Oregon and Willametle University, receiving a Bachelor of Arts degree from the University of Oregon, He received his law degree from Willamette University College of Law. Dan and Bill Paulus opened a law practice together in 1958, Dan married Mary Kay (Brown) Callaghan in 1961. After practicing law for 40 years, he retired from practice in 1999.

Dan loved rivers, and he devoted his life to helping preserve them as a serious conservationist, avid fly fisherman, and gifted photographer, He was one of the founders of The Steamboaters, a fly fishing and conservation club which originated at Steamboat Inn on the North Umpqua River, which he considered the most beautiful river he had ever seen, He was also a founder of the North Umpqua Foundation, Dan served as a director of those organizations as well as for The Museum of American Flyfishing, the Federation of Flyfishers, and the Salem Art Association, He served as a Commissioner on the Oregon Fish and Wildlife Commission, and served on the Willamette River Greenway Commission, He also served as house counsel for several flyfishing organizations, He received the Wild Trout Award from Oregon Trout and the Federation of Flyfishers' Brooks Memorial Life Membership award for his efforts in conservation and photography.

Dan was a member and supporter of the Steamboaters, North Umpqua Foundation, Federation of Flyfishers, Oregon Trout, Yellowstone Association, Trout Unlimited, 1,000 Friends of Oregon, Friends of Columbia Gorge, Nature Conservancy, Native Fish Society, American Museum of Flyfishing, High Desert Museum, Haig-Brown Kingfisher Society, American Rivers, Steelhead Society of British Columbia, Montana Trout Foundation, Water Watch of Oregon, Henry's Fork Foundation, and the Pacific Rivers Council, He was a Nikon Professional and a member of the International Association of Panoramic Photographers and the Portland Photographer's Forum, Dan fly fished and photographed many rivers in the Western United States, Canada, Alaska, Europe, Iceland, Central America, and South America, He was also a member of the golf team at Willamette Universit.

Dan's work has been published in Fly Fisherman, Fly Fisher, Rod & Reel, Outdoor Life, Newsweek, Country Gentleman, Outside, The Art of Angling Journal, Wild Steelhead and countless other publications.