The Milton Keynes Boundary Walk is a circular walk approximately 65 miles long around the boundary of the Milton Keynes Unitary Authority; it is waymarked with the Oakleaf symbol.

In 2012 a group a local geocachers divided the walk into sections and set a series of over 300 caches along the boundary.

More information about the walk and caches can be found at the website Caching the Boundary.

The blue section of the walk is approximately 5 miles long and starts at Weston Underwood, from where it runs north up to Kilwick Wood and then turns east, crossing the B5388 and finishing on the A428 at Oak Spinney / Hill's Copse. Most of the section is on public footpaths across agricultural land or farm tracks, so be prepared for challenging conditions underfoot. The route is marked by footpath markers all the way, however these are sometimes obscured by the undergrowth.

There are 24 caches in this section (plus this Bonus) and each cache contains a number to help you find this bonus cache, which is hidden near the middle of the walk.

This one is a 2 litre clip-lock tub, a long thin one that dry spaghetti will fit into - bring your own though because I didn't leave any in it.

To find it, you need to find the six bonus codes from the Blue section caches - A, B, C, D, E & F

When you have all six then calculate ;

• nnn = (D+B+C-A-E)*F
• www = (D*E) - (A*(B+C))

The cache is at :

• North 52^o 10.nnn
• West 000^o 43.www