Dorchester, a S. E. county of Maryland, bordering on Delaware and on Chesapeake bay, bounded N. and N. W. by Choptank river, and S. E. by the Nanticoke, both of which are here navigable; area, 640 sq. m.; pop. in 1870, 19,458, of whom 7,556 were colored. It has a level and partly marshy surface, with a soil sandy in some places and clayey in others. The Dorchester and Delaware railroad passes through it. The chief productions in 1870 were 122,460 bushels of wheat, 311,039 of Indian corn, 35,100 of oats, 65,949 lbs. of butter, and 15,368 of wool. There were 1,678 horses, 2,379 milch cows, 5,303 other cattle, 4,401 sheep, and 8,433 swine; 2 saw miils, 2 boat-building establishments, and 3 establishments for canning and preserving fruits. Capital, Cambridge.
Dorchester, formerly a town of Norfolk co., Mass., on Dorchester bay, an arm of Boston harbor, contiguous to South Boston, since 1869 constituting the 16th ward of the city of Boston; pop. of the town in 1860, 9,769; of the ward in 1870, 12,259. It was first settled by a party of English Puritans, headed by the Rev. John White of Dorchester, England, who landed at Nantasket, June 11, 1630, and established themselves within the limits of the town on the 17th of the same month. They soon erected a church, but no trace of it now remains. The first water mill in America was built here in 1633, and Dorchester has the honor of having originated about the same time the New England cod fishery.