Constitution River is the first foal and so far only runner of Chuppy (Le Havre), a maiden who raced twice and a full sister to Wonderful Tonight, winner of the Gr.1 British Champions Fillies & Mares Stakes, the Gr.1 Prix de Royallieu and the Gr.2 Hardwicke.

Second dam Salvation (Montjeu) won three races in France and bred six winners. Besides Wonderful Tonight they include Penjade (Air Chief Marshal), a minor stakes winner in the US, and Heartache Tonight (Recorder), placed at Group 3 level and fourth in the Prix Saint-Alary, then a Group 1.

Third dam Birdie (Alhaarth) won the Listed Lingfield Oaks Trial and had four other winners. The best of her three stakes performers is Hostess (Iffraaj), winner of the Grade 3 Providencia Stakes and dam of Military, a winner at two in Ireland and third in the Gr.3 Killavullan Stakes. Birdie is also the grandam of Nayeli (Sir Percy), a Listed winner in Italy.

Birdie's half-sister Fickle (Danehill), a Listed winner, produced Tarfah (Kingmambo), winner of the Dahlia Stakes, then a Group 3, and dam of Camelot (Montjeu), who won the Gr.1 2,000 Guineas, the Gr.1 Derby and the Gr.1 Irish Derby and became a leading sire.

Chuppy's second foal is the unraced two-year-old filly Sensational Filly (Mehmas), and she also has a yearling filly by Kodiac.