Alexander E. Borthwick was a Civil War veteran, railroad engineer and government servant who came to Portland in 1869. His son, William L. Borthwick, was a civil engineer and a Klansman. The collection includes correspondence, diaries, ledgers, photographs of the Borthwick family as wells as diaries and correspondence of the Saunders family who were related by marriage to William L. Borthwick.
James Henry Polhemus (1887-1965) was a civil engineer and inventor who became chief engineer of the Port of Portland, president of Portland General Electric Co., and the owner of the Willamette Tug and Barge Company. The papers consist of Polhemus's personal diaries, 1934-1964, correspondence, scrapbooks, photographs, and records of the various companies with which he was associated.