Upper Saxony
It was particularly to distinguish the lands from 'Lower Saxony', a concept which arose later in popular usage (though never enforced) as a term for the original Saxon lands in north and west Germany (where Low German dialects had spread), in what is now the state of Lower Saxony, as well as the adjacent Westphalian region, Holstein and the western part of today's Saxony-Anhalt north of the Harz range (Eastphalia).
Province of Saxony
On 1 July 1944, the Province of Saxony was divided along the lines of its three administrative regions. The Erfurt was merged with the Schmalkalden district of the Province of Hesse-Nassau and given to the state of Thuringia. The Magdeburg became the Province of Magdeburg, and the Merseburg became the Province of Halle-Merseburg.