On November 25, 2002, thousands of people marched through the streets of Mexico City and demanded, in the name of social justice, an end to the violence against women in northern Mexico. ‘Ni Una Más' (not one more) was their chant and is also the name of their social justice campaign. Their words referred to the hundreds of women and girls who have died violent and brutal deaths in northern Mexico and to the several hundred more who have disappeared over the last ten years. These Ni Una Más marchers, many working with human rights and feminist organizations in Mexico, are protesting against the political disregard and lack of accountability, at all levels of government, in relation to this surging violence against women. And the symbolic leaders of their movement are the Mujeres de Negro (women wearing black), who are based in Chihuahua City. In this article, I examine how the Mujeres de Negro demonstrate how feminist politics so often plays upon the negotiation of spatial paradoxes in order to open new arenas for women's political agency. For while the Mujeres de Negro of northern Mexico are galvanizing an international human rights movement that is challenging political elites, they are also reinforcing many of the traditional prohibitions against women's access to politics and the public sphere. And I explore how the Mujeres de Negro devise a spatial strategy for navigating this paradox in an increasingly dangerous political environment.