Isabel Grenfell Quallo (4 April 1893 – 21 September 1985) was a Congolese-born British-American domestic worker and community activist known for her involvement in the development of Druid Heights, in Marin County, California.

She then split the property with builder and jazz musician Roger Somers, and his wife Mary, and, initially with Isabel's help, they fostered an atmosphere which would attract many of those involved in countercultural movements, active in the United States between 1950 and 1970.

[1][2][5] Grenfell's father was a missionary and explorer, who mapped the territory of the Congo Basin, including Mount Cameroon and the Lungasi, Mungo, Sanga Yabiang, and Wouri Rivers, opening it up to mission work.

[1] She began her education in Bolobo in 1898,[3] but by 1903 had joined her older sisters Carrie and Gertrude, who were attending school at Walthamstow Hall in Sevenoaks, Kent.

[22][23] Quallo wrote the first letter and explained in her correspondences, her background, her difficult adjustment to life in the United States because of the prevalent segregation policies, and her relationships.

[23][26] She was concerned about difficulties that might arise because of their association[26] and expressed them to Gidlow saying, "A woman who discovers she is a lesbian and is a visible member of a minority has three strikes against her".

When Gidlow's mother, Alice May, suffered a stroke and needed permanent care, Quallo agreed to assist her, as she had previously worked as a nurse's aid.

[35] In 1954, hoping to escape from the increasing urbanization of Fairfax, Gidlow bought a 5-acre property in rural Marin County near Muir Woods.

[38] Despite the inability of single women to obtain credit at the time, Gidlow was able to borrow funds, after her friend Dorothy Erskine collateralized the loan.

After the death of their close friend, Ella Young, in 1956, Elsa named her portion Druid Heights.Both couples moved onto their respective separate properties shortly before the summer solstice of 1954.

Together they repaired the common piped water system for the buildings and future gardens which came from the local spring and had previously served the former chicken ranch.