The draw to go back to the area has been strong despite Manning leading Bristol City to sixth in the Championship, losing in the play-off semi-finals to Sheffield United.
Manning, 39, joined the Robins from Oxford in November 2023 having previously managed MK Dons and Lommel in Belgium.
Former Wolves boss Gary O’Neil and ex-Liverpool assistant Pep Lijnders were also spoken to and considered by the Canaries.
They sacked Thorup in April and put first-team coach Jack Wilshere in temporary charge but opted against giving Wilshere his first head coach role after the Canaries finished 13th in the Championship.
Watch all your favorite Amazon Prime Video Sports broadcasts live and free. Get access to NFL, NBA, NASCAR, WNBA, and more – all included with your Prime membership!