Touriga Nacional is produced all the way up and down Portugal. Given it’s full body, vibrant colour, and deep fruit flavour it’s an exceptionally useful wine to use in blends. For the most part that’s how it will come along, as part of a blend.
In the central and southern areas, like for Bairrada and Alentejo wines, it makes up part of the blend along with 2-3 other grape varieties. There are two areas in the north though which really throws it out there in centre stage. One is the famous Douro Valley, and the other is the Dão area.