Omg, I LOVE this question, although there are so many great locations to choose from that I also HATE this question, hahaha. I’ve lived in Portland for 24 years and absolutely adore this city, so many of the locations are meaningful to me.
My #1 choice has to be the St. John’s Bridge, which is the backdrop to many scenes on the show. The bridge is actually in way North Portland, and isn’t something that the characters would have much reason to be around, but it’s just such a gothic, atmospheric beauty, with the trees of Forest Park looming behind it – how could they not center it in the series? (It plays a central role in Colin Meloy’s Wildwood books as well.)
My #2 choice is the mysterious house from the pilot and the finale. (I’ve heard conflicting reports about its location, so I’ve never seen it myself.) There’s something primordial about this house that takes us right back to the original Grimm Fairy Tales. Because it hints back to the origin of the Grimm tales AND the origin of the Grimm series, it’s both enjoyably creepy and significant.
Weird fact: I drove my Nick and Juliette’s house a million times without ever realizing it was theirs. I only discovered it when I looked up the address online. It just never stood out to me somehow, which probably speaks to its authenticity – a lot of houses in Portland look like that.
Some other fave locations: In S1 E11 Tarantella, Nick and Monroe have coffee on a park bunch together in front of a 100yo building called Centennial Mills. The building has since been almost completely torn down, so this is a nice reminder. In S3 E3 A Dish Best Served Cold, the investigation centers around the old Bauerschwein-Blutbad feud in a real-life restaurant called The Raven and Rose. I actually had tickets to watch the episode live at the restaurant but didn’t feel good so I didn’t go (GAH!). S1 E15 Island of Dreams had a cool scene of an opium den kind of thing that was shot fairly close to where I lived at the time.