The Duchy of Lancaster is one of two royal duchies in England. It has landholdings throughout the region and elsewhere, operating as a property company, but also exercising the right of the Crown in the County Palatine of Lancaster. While the administrative boundaries changed in the 1970s, the county palatine boundaries remain the same as the historic boundaries. As a result, the High Sheriffs for Lancashire, Greater Manchester and Merseyside are appointed "within the Duchy and County Palatine of Lancaster".

When did the administrative boundaries for the Duchy of Lancaster change?