Stranorlar is a Civil Parish - it contains 2 towns Ballybofey and Stranorlar known as the Twin Towns because they are next to each other joined by the bridge over the River Finn. Stranorlar and Ballybofey would have been quite small at the time Griffiths Valuation was taken; the area outside the town would have been classified Stranorlar Townland, Ballybofey Townland but much of these townlands would now be part of the town.
Stranorlar is also the name given to the Registars District; you will need to get the death cert to determine where Alexander died - it could be anywhere in Stanorlar Registrars District.