] The first Henley Regatta was in 1839. However, teams from Oxford and Cambridge, or their individual colleges, had been rowing in the years before this date. Queen's, for example, first started in 1827. Well after JA's period.

Ande here's what I dug up about Ascot and Epsom Derby:

Ascot, founded in 1711 by Queen Anne, is one of the world's great racecourses.
It was while Queen Anne was out riding on the edge of Windsor Great Park that she noticed a natural clearing near the village of East Cote, now called Ascot. Queen Anne ordered a course to be laid out "for horses to gallop at full stretch" and so the Royal Racecourse was born. The first four-day Royal Meeting was held in June 1768 and has continued to the present day.

Epsom Derby
In 1779, two gentlemen,one of wich was Lord Derby, conceived the idea of a race to establish which horse was the best of its generation. Little did they realise when they tossed a coin to name the race that they were shaping the future of flat racing and breeding, and setting up the first of the great national sporting icons that capture the heart of both the nation and the world. Derby Day.

Have Jane Austen ever mentioned racing or betting or other types of playing for money in her novels or letters?
She sometimes set down to a game of cards herself, but that was purely for fun I guess. But would the men play for money at those cardgames they sometimes had at the balls?

Leif G-n