Pachycereus marginatus is a species of plant in the family Cactaceae. It has columnar trunks that grow slowly to 12 feet and may reach 20 feet in height. Stems are 3 to 4 inches in diameter, with ribs 5 to 7 in. Its central spine is about 3/8 inch in diameter with five to 9 radials and slightly yellowish in color.