We describe the baseline sociodemographic characteristics of the Health Resources and Services Administration's Special Programs of National Significance Women of Color (WOC) Initiative. Between November 2010 and July 2013, 921 WOC were prospectively enrolled in HIV medical care at nine sites, six urban (N = 641) and three rural sites (N = 280) across the US. We describe the study sample, drawing comparisons between urban and rural sites on sociodemographics, barriers to HIV care, HIV care status at study entry, substance use and sexual risk factors, and the relationship among these variables. Urban sites' participants differed from rural sites on all sociodemographic variables except age (median = 42.3). Women at urban sites were more likely to be Hispanic, less educated, single, living alone, unstably housed, unemployed, and to have reported lower income. More urban women were transferring care to HIV care or had been lost to care. Urban women reported more barriers to care, many relating to stigma or fatalism about HIV care. Urban women reported more substance use and sexual risk behaviors. A better understanding of how HIV care is embedded in communities or fragmented across many sites in urban areas may help understand barriers to long-term engagement in HIV care encountered by WOC.