Tucked in the rolling hills of western Howard County, Doughoregan Manor is a hidden touchstone to America's founding. It is the ancestral home of Charles Carroll of Carrollton, one of the 56 revolutionaries who signed the Declaration of Independence. Some consider it Maryland's Monticello. Unlike the famed Virginia estate, however, the 892-acre Doughoregan (pronounced "Doe-RAY-gun") property is owned by the Founding Father's direct descendants, who still live there. The intensely private family is considering selling some of Doughoregan for development and seeking tens of millions of dollars from the state and county to permanently preserve the rest. Perched on the...