Knotty Ash is a small area on the eastern fringe of Liverpool and neighbours the West Derby, Old Swan, Broadgreen, Dovecot and Huyton districts.

Knotty Ash railway station on the North Liverpool Extension Line formerly served the area, but this closed to passenger traffic in 1960.

The nearest current National Rail station is Broad Green, approximately a mile away from Knotty Ash, where fairly regular trains go to/from Liverpool Lime Street, and generally continue on to Wigan North Western, Manchester Victoria and Warrington Bank Quay stations.

In the 1960s, Knotty Ash was made famous in the United Kingdom by stand-up comedian and lifelong resident Ken Dodd, as the home of the dwarfish comic characters he called the Diddy Men.

In his BBC children's television programme Ken Dodd and the Diddymen (1969), the fictitious Diddyland, boasting the highest sunshine rate in the world, was situated in the centre of Knotty Ash.