Grey Valley is a former parliamentary electorate in the West Coast region of New Zealand.
The 1870 electoral redistribution was undertaken by a parliamentary select committee based on population data from the 1867 New Zealand census.
[1] The Taramakau River formed the southern boundary of the electorate, from the mouth all the way to Harper's Pass (a historic alpine crossing).
The main population centres in this configuration were Greymouth and the coal mining towns in the Brunner Borough (which itself was not constituted until 1887).
The main population centre gained by this boundary adjustment was Reefton.