Danielle Hill has a secret, one she shares with dozens of other residents of Baltimore public housing. It goes like this: They don't live in the city. Instead, they live in Anne Arundel, Baltimore, Harford and Howard counties, in houses purchased by the Housing Authority of Baltimore City. Thousands more have moved to the counties with special rent subsidies in a companion program. Hill's family is among nearly 10,000 black women and children who have moved into overwhelmingly white, prosperous suburbs through a court-ordered relocation program designed to combat the intense inner-city segregation and poverty forged by decades of discrimination....