There are three major rivers named 'Avon' (pronounced 'ay-vun') in southwestern England and a few others scattered over Great Britain (such as the one that flows into the Forth Estuary between Glasgow and Edinburgh). You will frequently hear people refer to the 'River Avon', although this is redundant, since the word derives from the Welsh afon, meaning 'river'.
The Avon that first springs to the minds of most non-Britons is the 'Warwickshire Avon', which drains the southern part of the West Midlands. It rises near the Leicestershire hamlet of Husbands Bosworth1, halfway between Leicester and Daventry on the western slopes of the Northamptonshire Uplands. Part of its uppermost course has been used for the Grand Union Canal which emerges from a tunnel just west of H.B. The river forms the border between Leicestershire and Northamptonshire until it crosses the A5 just west of Rugby, entering Warwickshire. It flows through Rugby then flows west into the outskirts of Coventry, then turns south to flow through Royal Leamington Spa and Warwick. The river continues southwest into Stratford-upon-Avon2. The river then flows into Worcestershire and through Evesham, then turns west until it reaches Pershore, then almost due south until it flows into the Severn just west of Tewkesbury (just inside Gloucestershire). The Avon is navigable (or has been made navigable) for the 26 miles from Tewkesbury to Stratford-on-Avon, and is a favorite of pleasure boaters who follow it as part of the 'Avon Ring'.
The 'Bristol Avon' rises on the eastern slopes of the Cotswolds near the Gloucestershire town of Tetbury. It flows south into Wiltshire through Malmesbury and Chippenham, then slowly bends westward until it meets the Kennet-Avon Canal at the town of Bradford-on-Avon. Continuing downriver into Somerset (with the canal running parallel), Avon has chewed a winding path through the southern end of the Cotswolds, where it flows through Bath. It then flows through the heart of Bristol, then out into the Severn Estuary/Bristol Channel at Avonmouth. The Bristol Avon has been made navigable as far as Bath, the western terminus of the Kennet-Avon Canal. However, the river may have been navigable much further upriver in the past: It has been suggested that the builders of Stonehenge floated immense bluestones on rafts from Wales up the Bristol Channel and the Avon as far as Bradford-on-Avon, from where they were hauled overland.
The 'Salisbury Avon' rises in the Vale of Pewsey in eastern Wiltshire, a center of Neolithic culture. Some of its upper tributaties are intercepted by the Kennet-Avon Canal mentioned earlier, but the river flows south through a gap between the Wilsford Downs and the Pewsey Down into the Salisbury Plain. Most of the settlement of the Plain is concentrated in the Avon valley. Avon flows through a string of small hamlets (and a military proving ground) until it reaches Amesbury in the middle of the plain, and flows right past Stonehenge. It winds south past more hamlets until it reaches Salisbury. The southern entrance to the Avon valley was controlled for millenia from Salisbury's predecessor, the fortress/castle now called Old Sarum. On the Avon right beneath the mound of Old Sarum is another village called 'Stratford', but this is called 'Stratford sub Castle' to avoid confusion. Avon continues south into Hampshire through Fordingbridge and Ringwood, where it becomes the border between Hampshire and Dorset. Avon finally empties into Christchurch Harbour3 at Christchurch, just east of Bournemouth.
1Not the site of the 1485 battle which ended the Wars of The Roses. 'Market Bosworth
', the site of that battle, lies about 20 miles (32 km) to the northwest.
2For obvious reasons, the Warwickshire Avon is sometimes called the 'Stratford Avon'.
3A lagoon connecting with Christchurch Bay, and protected by Hengistbury Head.