Nkoranza is the administrative capital of the Nkoranza South Municipality. In 2012 it was upgraded to a municipality status by LI 2089. It covers a total land area of 923 square kilometres. The population of Nkoranza South Municipality, according to the 2010 Population and Housing Census, is 100,929 representing 4.4 percent of the region’s total.
The St. Martin de Porres parish was established around the year 1956. Among the founding members were Mr. Kwabena Boateng, Mr. Michael Adu, Mad. Mary Baffoa, Maame Sampah, Mad. Mary Sakyiwaa, Maame Akosua Afrah, Maame Therea Boahemaa and Op. Yaw Opoku It was made a parish on 5th May, 1971, with Rev. Fr. Martin Wesseling as its first resident pastor, and the first Mass was said on that day. its longest serving Parish Priest was Msgr. John Nkrumah.
When Techiman Diocese was created, Rev. Fr. Andrews Addai was appointed as the Parish Priest until he was succeeded by Rev. Fr. Dominic Yaw Assuahene in 2012. Rev. Fr. Samuel Kofi Adjei is the current Parish Priest of Nkoranza, Assisted by Rev. Fr. Matthias Ackah. The Parish celebrates its Feast Day on 3rd November.