The town of Warwick was founded on the banks of the River Avon in 914 AD. Kenilworth and Whitnash get mentions in the Domesday book of 1086 whilst Leamington was largely created in the 19th century.
Kenilworth
The Kenilworth town website contains details.
Kenilworth Abbey, Abbey Fields, Kenilworth, Warwickshire
Founded in the 1120s, the Augustinian monastery dedicated to St Mary grew into one of England's wealthiest abbeys. The abbey was dissolved by King Henry VIII in 1538 and most of the buildings demolished. Ruins of the abbey can still be seen in the Abbey Fields, together with more substantial remains in the form of a Gatehouse and a building usually called the Barn.
The abbey ruins are open at all times. The exhibition in the Barn is open 2pm - 5pm on Sundays during summer. The Barn is managed by volunteers from Kenilworth History and Archaeology Society and other local organisations. Entrance is free.
More information on the Abbey can be found at Our Warwickshire.
The medieval gatehouse - part of the ruins of Kenilworth Abbey
Leamington Spa
There are many local history and heritage resources at The Royal Pump Rooms.
You can also buy books on the history of Leamington and the Royal Pump Rooms.
Images of Leamington in the past
Warwick
Visit the Warwick town council website for a brief history of Warwick. Visit the Warwickshire museums section of the county council site for details of the Market Hall museum and St John's House museum in Warwick.
Whitnash
Visit the Whitnash town council website for details of the history of Whitnash.
Wikipedia
The free, editable online encyclopedia contains details of the history of Kenilworth, Leamington and Warwick.