The townsite of Nanson is located in the Chapman Valley, 455 kilometres north of Perth and 34 kilometres northeast of Geraldton. The district was first settled in the 1850s when Michael Morrissey established "Mt. Erin", but it was not until 1909 when the Government planned the Upper Chapman railway that there was a move for a townsite in the area. In 1909 local farmers petitioned the Minister for Lands to lay out a townsite at the "12 1/2 mile siding" on the railway. When the railway was opened in 1910 the siding was named Lauder Siding after a local farmer, but residents in the area petitioned the Minister for Lands to name the proposed townsite "Nansonville", after John Leighton Nanson MLA who was the local Member of Parliament, and also Attorney-General in 1910. The Minister agreed to the townsite being named Nanson, and it was gazetted in October 1910. The siding name was changed by the Railway Department in 1912 to Mount Erin, as this was the name locally used for the place. In 1915 confusion between the siding and townsite names resulted in the siding being renamed Nanson.