During the shooting of McQ, from June 4 to August 1973, the movie company used several Seattle locations. Wayne's hard boiled cop trades shots with the mobsters in the rear of the PacMed building. 

McQ uses the back entrance on 12th Ave which has not changed over the years. In hot pursuit of the van, McQ then races down South Dearborn Street. 

During the six weeks on location in Seattle, Wayne lived aboard the Wild Goose, very much in character as Seattle detective Lon McQ also lives on a boat. The Wild Goose was berthed at the Seattle Yacht Club

 

The boat harbor where McQ lives, however, is Northlake Marina at 1059 North Northlake Way. 

The Aurora Bridge appears prominently in the sequence when McQ shoots the hitman. The Fremont Boat Company which is seen in the background is still situated there...

.....and so is the wooden stairway where McQ is ambushed and then returns fire. 

One of the highlights of a John Wayne location tour in Seattle is the J&M Café at 201 1st Avenue South: this is where McQ walks up to the bar to learn that his friend just died and...

..., in a rage of fury, beats up Santiago in the toilette. The restaurant remains virtually unchanged. The restroom took up the space that is now a storage room. 

McQ keeps busy; he meets the local drug-dealer (Roger E. Mosley) inside the Coliseum, which is now Key Arena at 305 Harrison St.

The climatic car chase was shot at the further edge of the Olympic Peninsula, at Ocean Shores. 

Stunt coordinator Ronnie Rondell had chosen the special section of the pristine beach at Grenville Bay, just off State Route 109, north of Moclips, for the signature stunt of the movie: the first time the flippping of a car was achieved with the "Needham Cannon".

The final scene, McQ's conclusion, was shot in the nearby beachfront town of Moclips.  Wayne points to a bar, saying: "Let's get a drink." 

And it's still there. Even though you can't get a drink. The wooden shack stands at 2nd Streed and Pacific Avenue.

During the shooting at Ocean Shores, John Wayne and the crew lived at the Polynesian Resort at 615 Ocean Shores Blvd. That's the layout of the "Poly"...

 

 

...and here's a look inside. Wayne knew the “Poly” well; the kitchen staff remembers he found their cooking to his taste. He returned every once in a while, when the Wild Goose cruised the waters off the Washington coast.