Pennington derives either from the Old English meaning "a farmstead or small holding paying a penny rent" or a "settlement associated with a man named Pinna".

Historically, Pennington formed part of the Hundred of West Derby, a judicial division of southwest Lancashire.

Under the terms of the Poor Law Amendment Act 1834 the townships formed part of the Leigh Poor Law Union which was established on 26 January 1837 comprising an area covering the whole of the parish of Leigh and part of Winwick.

[10] The township of Pennington covered an area of 1,482 acres, much of it below 75 feet above mean sea level, but slightly higher to the north of Pennington Brook, which crosses the township from west to east, The highest point is a little over 100 feet in the south-west near Aspull Common.

The geology consists of the pebble beds of the bunter series of the new red sandstone, with an area of alluvium in the low ground by the Pennington Brook.

The Bridgewater Canal crosses the township for a short distance on the south side of Leigh town centre.