Martha Bouton "Mamah" Borthwick (June 19, 1869 – August 15, 1914) was an American translator who had a romantic relationship with architect Frank Lloyd Wright, which ended when she was murdered.

Wright built his famous settlement called Taliesin in Wisconsin for her, in part, to shield her from aggressive reporters and the negative public sentiment surrounding their non-married status.

In April, 1911, Wright's mother purchased land in her family's valley near Spring Green, Wisconsin[9] so that her son could begin designing a home in which to live with Borthwick after her planned divorce.

[10] She spent time with her children in Canada through the summer waiting to divorce Edwin Cheney, which she did on August 5, and legally returned to her maiden name.

[11] The editor of the Spring Green newspaper (the Weekly Home News) condemned Wright for bringing scandal to the village.

[12][13] Chicago newspapers criticized Wright, implying that he would soon be arrested for immorality, despite statements from the local sheriff that he could not prove that the couple was doing anything wrong.

[14] On August 15, 1914, Julian Carlton, a male servant from Barbados[15] who had been hired several months earlier, set fire to the living quarters of Taliesin and murdered seven people with an axe as they fled the burning structure.

[12][17] Thomas Fritz also survived the mayhem, and Weston helped to put out the fire that almost completely consumed the residential wing of the house.

The death of Borthwick is described in the book The Rise of Endymion by Dan Simmons in a back-story of the persona of Frank Lloyd Wright.