It was renamed more than 150 years ago in 1856, after politician Isaac Featherston.
But that name was never made official.
South Wairarapa mayor Viv Napier said she was flabbergasted when she found out.
"A group of people in Featherston, headed by a guy called Perry Cameron, found out that Featherston's name was not actually officialised - if that's even a word.
"Everyone knows Featherston and everyone would just assume that it is gazetted as Featherston, but apparently it is not."
Napier said the group approached the community board and suggested it might be a good idea to go through the New Zealand Geographic Board Ngā Pou Taunaha o Aotearoa to get it made official.
The board is the authority on all New Zealand place names and secretary Wendy Shaw said it would put the proposal to make the name official to the public next month.
Napier said she expects most people will want to keep the name.
"I can't imagine that too many people would get too carried away with any other names.
"Featherston's a very proud town and they're very proud of the Featherston name so I can't imagine there'd be too many people from Featherston who would be wanting to change it.
"Who would know what comes out in public consultation though."
Napier said the whole debacle had got her thinking about whether it was a wider issue.
"Who knows if there's a whole lot of other places in New Zealand that haven't actually had their name made official. And whether it's common, or whether it's rare, or what I don't know. But it is quite weird."
Shaw said the public will have three months to have their say on making the name official.
public views on this proposal over a three month period, starting late November 2017."Details on making submissions will be made available at that time."
Featherston was first known as Burlings, after Henry Burling, one of the first settlers to the area.
In 1856 the provincial government surveyed the spot for a town, naming it after its superintendent, Isaac Featherston.
The name is visible in a number of attractions in the town, including the Featherston Heritage Museum, which tells the story of the historic Featherston military base.