Bierton Clay Pit is a 0.07-hectare (0.17-acre) geological Site of Special Scientific Interest in Bierton in Buckinghamshire.

[3] This disused clay pit exposes a section from the late Jurassic Kimmeridgian and Tithonian stages, between about 157 and 145 million years ago.

It is the only exposure of the northern end of the Portland Beds, and shows the relationship between the Beds and the Hartwell Clay.

It also gives evidence of a period of erosion followed by a rise in sea level.

[4] It can be viewed from a footpath between Barnett Way and Brick Kiln Lane.