Much of the area that John Clare knew as Emmonsails heath is now arable farmland. The heath would formerly have stretched across the top of the ridge south of Helpston, lying roughly in the area between the current Castor Hanglands nature reserve and Swaddywell Pit, extending west towards Southey Wood.
It would have contained large areas of grassland, gorse and heather. As common land it would have provided grazing land and, in winter, fuel for many villagers. It was also a frequent camp for travellers, with whom Clare had a particular affinity.
Relic areas of heath remain at Castor Hanglands and areas of limestone grassland can be found at Barnack Hills and Holes and Swaddywell Pit.
Clare spent many hours on the heath and wrote about it frequently, describing it in many different seasons, including winter
I love to see the old heath’s withered brake
Mingle its crimpled leaves with furze and ling
While the old heron from the lonely lake
Starts slow and flaps his melancholly wing
And oddling crow in idle motion swing
On the half-rotten ash-tree’s topmost twig
Beside whose trunk the gipsey makes his bed
Up flies the bouncing woodcock from the brig
Where a black quagmire quakes beneath the tread
The fieldfare chatter in the whistling thorn
And for the awe round fields and closen rove
And coy bumbarrels twenty in a drove
Flit down the hedgerows in the frozen plain
And hang on little twigs and start again
Many of the sights and sounds that Clare would have known can be seen and heard today in places such as Castor Hanglands, including the woodcock, fieldfare and the long-tailed tit (bumbarrel). Others such as the nightjar, that Clare would have heard calling from the heath, have disappeared entirely from the area.