PORTSMOUTH, a town of the United States of North America, state of Ohio, on the right bank of the Ohio, at its confluence with the Scioto, 115 miles above Cincinnati, and 90 S. of Columbus. It contains a court-house, a bank, six or eight churches, two large schools with 13 teachers and about 700 pupils, two iron foundries, a forge, and a nail factory. Iron, coal, and good building-stone are obtained in abundance in the vicinity. Pop. (1850) 4011; (1853) about 5000.