Nelson is a consolidated city and unitary authority on the eastern shores of Tasman Bay at the top of the South Island of New Zealand. It is the o…Nelson is a consolidated city and unitary authority on the eastern shores of Tasman Bay at the top of the South Island of New Zealand. It is the oldest city in the South Island and the second-oldest settled city in the country; it was established in 1841 and became a city by British royal charter in 1858. It is the only consolidated city-region in the nation.