Creator Abi Morgan has openly admitted she borrowed the core idea from the late Anthony Minghella, who directed the 1990 fantasy film Truly, Madly, Deeply, in which a grieving woman's dead boyfriend appears to come back to life.

Morgan said her inspiration for depicting a character who lives with voices in his head partly came from her own experience of talking out loud to herself, which she realized was a comfort, likening it to the voices we carry from our past or future.

Stellan Skarsgård explained that there was little research he could do for his role as DI River because the character's psychological condition doesn't exactly correspond to any real diagnosis, being different from schizophrenia since River retains empathy.

To film scenes involving River's hallucinatory 'manifests', the crew would first shoot the scene with the actor playing the manifest present, then reshoot the exact same scene and blocking without that actor, allowing Skarsgård to react as if the person were still there.

Filming for the series began in London in October 2014 and took place across at least eight London boroughs, including Lambeth, Islington, Camden, Hackney, Southwark, Redbridge, Newham, Tower Hamlets and Lewisham, using landmarks such as the Globe Theatre, Millennium Bridge, Southwark Park and Clerkenwell Road.

The series used the song 'I Love to Love (But My Baby Loves to Dance)' at the start and end of the first episode and again at the end of the final episode.

Lesley Manville received a nomination for the 2016 BAFTA TV Award for Best Supporting Actress for her role as DCI Chrissie Read.

Critics praised the show highly, with The Daily Telegraph awarding five-star reviews to both the first and final episodes and comparing River favorably to other acclaimed British dramas of the year like London Spy, Humans and Wolf Hall.