Good maps of Portugal are few and far between – and very hard to find once you’re in the country. It’s a VERY good idea to buy any maps before you get there.
For more general information about maps, see the Roads & Maps page.
Online sources for buying Portugal maps include:
Instituto Geografico do Exercito – Portugal’s Army Geographic Institute produces large-scale topographic maps
Mapsworldwide.com – seems to have a good selection, including the detailed military maps
Stanfords – leading map retailer – has Michelin, Turinita, IGE maps etc
The Map Shop – independent retailer in Upton upon Severn. Pretty basic website but has a good range.
And – of course – you can also get cheap Michelin maps (from £4.49) via Amazon.