Most family members to complete an ultramarathon
Holdaway Family
11 people
United States (Antelope Island)

The most family members to complete an ultra marathon is 11 and was achieved by the Holdaway family (USA) at the Buffalo Run Ultramarathon in Antelope Island, Utah, USA, on 21 March 2015.

The family members that participated in this record attempt were Chris Holdaway, Wendy Holdaway, Jeff Holdaway, Grant Holdaway, Dan Nielson, Matt Holdaway, Holly Taylor Dayley, Hope Taylor, Faith Taylor, Danielle Taylor, and Cameron Holdaway.