Alexander's possession of Badenoch was unaffected by the restoration of the Earldom of Moray to John Dunbar in March 1372, nor were the territories of John MacDonald, Lord of the Isles, in Lochaber—similarly with the lands of Urquhart (south of Inverness) which had been granted to David Stewart, Earl of Strathearn and King Robert's eldest son with his second wife, Euphemia. Alexander further extended his territorial gains in 1371 by leasing the Urquhart lands from his younger half-brother and then obtained possession of the Barony of Strathavon bordering his Badenoch lands. In October 1372, Alexander was given the Royal Lieutenancy for those lands outwith the Earldom of Moray north and west of Inverness and added lands in Aberdeenshire and north Perthshire. In the same year, he was Royal Justiciar in the Appin of Dull in Perthshire which meant that Alexander held crown authority from north Perthshire to the Pentland Firth.