Sisters Cindy Flint and Carol Olsen, along with their mother Donna Flint, made the nearly 300-mile trip to Idaho with their ticket locked in a fireproof safe.
Cindy Flint says she went a step further, and slept with the safe in her hotel bed.
The women claimed their prize Monday.
Lottery spokesman David Workman says other winners have taken precautions, but the Flint family may be the first to arrive in lobby of the Idaho Lottery headquarters with a safe in tow.
The women bought their ticket at a store in Franklin, Idaho, near the state border with Utah.