The tunnel was built as part of the London and Birmingham Railway and designed by its chief engineer, Robert Stephenson.

He took the line north-west from Roade Cutting, bypassing Northampton, partly because reaching it would require a gradient greater than the ruling 1:330 that Stephenson was determined to preserve.

[1] The tunnel runs in a straight line underneath the A5 main road between Weedon and Towcester from about northwest to southeast.

It has large, splayed abutments which meet brick wing walls, parallel to the tracks, and terminate in hexagonal pillars with square stone caps.

[4] During the 2000s, in preparation for the introduction of the British Rail Class 390 tilting trains, which would enable regular operating speeds of 125 miles per hour (201 kilometres per hour) along this section of the line, it was determined that the Stowe Hill tunnel would, without modification, cause such pressure changes to trains traversing it at high speed as to exceed passenger comfort levels.