Who was Lisa Montgomery, why was she executed and when was the last female inmate executed in the US? Luke O'Reilly The first female inmate on federal death row has been executed by the US government in nearly seven decades. Before that, the last woman to be executed by the US government was Bonnie Heady, who was put to death in a gas chamber in Missouri in 1953. A federal judge had granted a stay in Montgomery’s execution on Tuesday, citing the need to determine her mental competence. But the US Supreme Court then cleared the way for her execution.