Ainsdale is a village situated three miles south of Southport, of which it is a suburb. It was listed in the Domesday Book as Einulvesdel. Deriving from Old Norse name Einulfsdalr, this apparently was the valley occupied by a Scandinavian by the name of Einulf.

Ainsdale formed part of Sir Cuthbert Halsall of Halsall's estates during the early part of the 1600s.  In 1634 the ownership was passed to Robert Blundell. The lands were passed from generation to generation within the Blundell family and remained in their ownership until the mid-1900s.

Throughout the 1800s Ainsdale remained an agricultural community. Prior to the Industrial Revolution fields and farms in the locality were small and land was enclosed.

The railway arrived in 1848.

Ainsdale became part of the County Borough of Southport in 1912 after being part of Birkdale, though it remained a separate parish to Southport until 1925. Although now in the administrative county of Merseyside it is still in the County Palatine of Lancashire.

Today the village and roads leading to the beach are middle class areas, with some new modern developments around the station including the addition of the private estate Village Row in 2006 and the Belway estate in 2013.