Situated some four miles north-east of Wimborne in the northern part of the Poole Basin lies Holt Heath NNR, a reserve dominated by one of the largest single remaining blocks of heathland in Dorset. The heath occupies approximately 400 hectares (1000 acres) and all typical heathland habitat types are represented, with a mosaic of dry and humid heath on the higher ground and large mire expanses forming where the drainage is impeded on the lower-lying parts of the reserve.