Long Rock, Marazion and St Erth is an electoral division of Cornwall in the United Kingdom which returns one member to sit on Cornwall Council.

It was created at the 2021 local elections, being formed primarily from parts of the former divisions of Marazion and Perranuthnoe and Gwinear-Gwithian and St Erth, as well as with a small part of the Ludgvan division.

[4] A by-election was held after Tara Sherfield-Wong resigned in 2022 for health reasons.

[5] Sherfield-Wong had faced claims that she was neglecting her role, including by five parish councils in her division.

[6][7] Upon his election, Martin said his win "sends a message of discontent" about plans for a Mayor of Cornwall.