Byron Clark Denny, 74, an economist who retired in 1969 as the officer of international activities for the Department of Interior's Bureau of Land Management, died of cancer Thursday at the Chevy Chase Nursing and Convalescent Center in Silver Spring. He lived in Washington.

Mr. Denny was a water planning analyst with the Bureau of Agricultural Economics before joining Interior's Bureau of Land Management in 1942. He served as chief of the Bureau's land classification branch, specializing in public land management and conservation of renewable resources, before being named officer of international activities in 1948.

In this capacity, he was responsible for helping Egypt, Iraq, Morocco, Jordan, the Philippines and South American countries utilize their natural resources. He also represented the United States at numerous international conferences on public land management. At his retirement, he received Interior's Distinguised Service Award, the department's highest honor.

Mr. Denny was born in Waynesburg, Pa. He graduated from Pennsylvania State University, earned a master's degree in economics from Rutgers University, and completed course work for a doctorate in economics at the University of Wisconsin.

He was a member of Chevy Chase Presbyterian Church.

Survivors include his wife, Emily, of Washington; two daughters, Emmy Lou Gooch of Huntingdon, Pa., and Patricia D. Baker of Kensington, and three grandchildren.

The family suggests that expressions of sympathy be in the form of contributions to the American Cancer Society, or to Children's Hospital National Medical Center, Washington.