The rooftop deck at The Society Hotel - Portland is a beautiful venue you can book out or bring up your coffee or cocktial from the main cafe/lounge on the ground floor.
The society hotel is a cool hostel / hotel concept with multiple locations near Portland (the Hood River location is a favorite). The main event is down stairs - the lobby and cafe serves beer/wine and cocktails and the rooftop deck is just that - a deck - more than a bar.
You an bring up the beverages from downstairs if you like or - and this is rare in the rooftop bar world - just bring up a book and read. It's more loungey and laid back that other venues - so don't worry about a dress code.
You can book the rooftop for specific events if you have a special occasion and the 360º view in the midst of downtown is a great one.
This is great choice for a laid back afternoon cocktail or even a coffee at different times throughout the day. Have fun.
Important: there is no bar service on the roof.