Cosmah (April 4, 1953 – 1979) was an American Thoroughbred racehorse. While not known for her racing career, she is well known for being the dam of Tosmah and Halo, both of whom were top level race winners.

Cosmah won the 1955 Astarita Stakes due to the disqualification of another horse named Dark Vintage.^[2]

Cosmah's descendants include:^[3]

• Tosmah (1961), filly: Frizette Stakes, Astarita Stakes, Mermaid Stakes, Arlington Classic, Beldame Stakes
• Maribeau (1962), colt: Fountain of Youth Stakes
• Halo (1969) colt: Lawrence Realization Stakes, Tidal Handicap, United Nations Handicap
• Queen Sucree (1966), filly: Dam of 16 foals out of which were 10 winners. Many of her offspring were successful broodmares and sires. One of Queen Sucrees daughters was Princess Sucree, dam of Group 2 winner Rasheek and third dam of Group 2 winner Hyper.

Cosmah's other descendants include:^[3]

Through Tosmah: 1973 New Jersey Futurity winner La Guidecca.

Through Halo: Sunny's Halo, Sunday Silence, Devil's Bag, Glorious Song, Saint Ballado and Goodbye Halo

Through Queen Sucree: 1974 Kentucky Derby winner, Cannonade.