Let KAYAK do the searching
Based on KAYAK hotel searches, the most popular destination is Porto (68% of total searches to Northern Portugal). The next most popular destinations are Vila Nova de Gaia (25%) and Maia (Porto) (5%). Searches for hotels in Lamego (3%) are also popular.
KAYAK users have found double rooms in Northern Portugal for as cheap as $40 (Maia (Porto)) in the last 3 days. The average price is $251.