In the 1887 electoral redistribution, although the Representation Commission was required through the Representation Act 1887 to maintain existing electorates "as far as possible", rapid population growth in the North Island required the transfer of three seats from the South Island to the north. Ten new electorates were created, including Masterton, and one former electorate was recreated.[1]
The Masterton electorate's boundaries were roughly based on those of the Wairarapa North electorate that it replaced, although it was not an exact match. The electorate ran from the Tararua Ranges down to the sea, with its northern boundary just north of Eketahuna and its southern boundary just south of the largest Wairarapa town of Masterton.[2]
^"The General Election, 1938". National Library. 1939. pp. 1–6. Retrieved 8 February 2012.1-6&rft.pub=National Library&rft.date=1939&rft_id=https://atojs.natlib.govt.nz/cgi-bin/atojs?a=d&d=AJHR1939-I.2.3.2.36&rfr_id=info:sid/en.wikipedia.org:Masterton (New Zealand electorate)" class="Z3988">