This annual plant is now a threatened species, although it was formerly scattered along the eastern coast of the United States, its native range.

The lengthy viability of these seeds may account for the reappearance of Amaranthus pumilus in places where it had formerly vanished.

Although the seaside amaranth is found in the neighborhood of other beach plants, it is intolerant of all but American sea rocket (Cakile edentula).

[1] It is listed as a special concern and believed extirpated in Connecticut,[5] as threatened in North Carolina, and as endangered in Maryland, New Jersey, New York, and Rhode Island.

[6] Threats include disturbance of its beach habitat through development, construction of seawalls, off-road vehicle activity, and other forces.