It flows from east to west between the hills on both sides, giving the Rockville Historic District a steeply-rolling terrain. There is a total of 51 streets within the Rockville Historic District. The Rockville Historic District was listed on the National Register of Historic Places in 1984. Portions of the content on this web page were adapted from a copy of the original nomination document. [â ] Adaptation copyright Â©2010, The Gombach Group.