Landscape Gardener, William Horvath, Landscape Designer, Snohomish, WA, c. 1918; Principal, Otto E, Holmdahl, Landscape Gardener, Seattle, WA, c. 1920-; in 1931, his office was located at 4534 University Way Office #112 in the University District; from 1932 into the 1960s, Holmdahl occupied space at 711 Broadway North in in the Capitol Hill Neighborhood. (This information comes from Duane Dietz, "Architects and Landscape Architects of Seattle, 1876-1959," typescript, 1994, Built Environments Library, University of Washington.)

Born in Sweden, Holmdahl lived in Snohomish, WA, in the Bells Court Apartments (#16) on 09/12/1918; At this time, he was a native of Norway. Holmdahl came to Seattle, WA, by c. 1920.

Otto Holmdahl married Audrey Holmdahl before 09/1918.

Holmdahl served as the Principal Landscape Architect for the Seattle World's Fair of 1962. SSN: 534-38-8014. At age 35, Holmdahl's World War I Draft Registration Card indicated that he was of medium height and build, with green eyes and brown hair.