Julia Morgan was born in New York in January 1865. Around 1886, she moved to Portland, Oregon, where she attempted to establish an artistic career. On October 17, 1888, she married Osmon Royal (January 3, 1856-December 31, 1910), the son of Charles Wesley Royal (1823-1895) and Rachel Eliza Powell Misner. He graduated from the Boston University School of Medicine in 1885 and practiced medicine in Portland. Julia and Osmon Royal had one son, Osmon V. Royal.
May McKoon, whom Julia Morgan referred to as "sister," lived in Long Eddy, New York, with her husband Horace. They had at least two children, Margaret and Morgan. Margaret A. McKoon lived with Julia and Osmon Royal, her aunt and uncle, from 1889-1893.