Dallastown, borough (1990 pop. 3,974), York co., S Pa., suburb, 6 mi/9.7 km SE of York; 39°53'N 76°38'W. Mfg. (fabricated metal prods., electronic equip., wood prods., paper prods., concrete, machinery). Agr. area (wheat, corn, alfalfa, poultry, apples, livestock, dairying). Inc. 1867.