There's been a Oeiras HEX around for quite a while, but so far below anyone's radar it's gone largely unnoticed. (With a NATO Command HQ close by, the radar silence might be intentional )

This might be a new one - it's on the Cascais motorway, connected to the national system, close to some of Lisbon's satellite business parks.

You'd really need a car to use it. Oeiras is solid comuter-land, a major stop and part-time railway terminus mid-way (15 minutes) from both Lisbon and Cascais. From the station you'd certainly need a bus or taxi.