1GL Bolt: Birdforth Bridge   

Bolt in East face of South pier of Birdforth Bridge ; 4.79 ft. above surface [1GL, Selby to Newcastle-upon-Tyne, Mark No. 69]; BOLT BIRDFORTH BR NE PARA SE SIDE BECK NE FACE (35.4138m ODN, 1.4m AGL, 3rd order).

Location
Grid reference: SE 4865 7571.
Landranger 100: Malton & Pickering, Helmsley & Easingwold.
Structure: Bridge.
Waypoint: BT0735.

Neighbouring Bench Marks

BM	Thormanby, Black Bull Hotel 1.08km to the southeast.
BOLT	Thirkleby Bridge 2.28km to the northwest.
BM	Stockhill Green 3.72km to the northwest.
BOLT	Raskelf Bridge 4.94km to the south.
BOLT	Bagby, Church 5.43km to the northwest.

The nearest fundamental bench mark is Northallerton, 18.85km to the north.

First Primary Levelling, England & Wales (1840-60)
This bench mark was used during the First primary levelling, England & Wales, and was levelled with a height of 116.5040 feet [35.5104 metres] above mean sea level (Liverpool datum). It was included on the Selby to Newcastle-upon-Tyne levelling line. The surveyor's description was Bolt in East face of South pier of Birdforth Bridge ; 4.79 ft. above surface.