Forest Arthur Harness (born June 24, 1895) was a Republican member of the United States House of Representatives from Indiana. He represented Indiana’s 5th Congressional District and served as a historical member of Congress during the mid-20th century. His congressional career is most notable for spanning the decade immediately preceding and following World War II.

Harness began his service in the U.S. House on January 3, 1939, and remained in office until January 3, 1949. Over the course of these ten years, he served five terms as a representative. During this period, he participated in the legislative work of the House as a member of the Republican Party, representing the interests of his Indiana constituents at the federal level.

Throughout his tenure, Forest Arthur Harness held the formal role of Representative and is recorded as a former officeholder. While specific committee assignments, office room, and contact details are not listed in the available record, his decade-long service from 1939 to 1949 situates him among the notable Indiana Republicans who served in Congress during a transformative era in American political and social history.