Swellands Reservoir & its neighbour, Black Moss Reservoir are on the Pennine Way between A62 to the north & A635 to the south & also bounded by Saddleworth to the W & Wessenden to the E.
The cache location was chosen because it is sheltered, secluded & quiet.
The best way to get to the cache is by parking opposite the standing stone on the road south of Pule Hill then following a path south which joins a leat contouring round the hill to the reservoir. This gives good views down to Marsden.
Swellands Reservoir was built in 1810 as a supplementary feed to the Huddersfield canal under construction. Just as the completion date was in sight, a final disaster occurred on November 29th 1810 when the Swellands Reservoir failed. The Colne valley from Marsden to Paddock was inundated and many mills and factories wrecked under the force of the waters. Six people lost their lives during this terrible 'Black Flood'.
Today Swellands Reservoir is owned by the Canal and River Trust who began repair and maintenance work on these remote and historic reservoirs to bring them up to modern standards. Swellands Reservoir still lay empty in 2026, it is unclear when the new spillway and other works here will take place.