Even though other sites (Pakefield and Happisburgh in East Anglia) have now provided the earliest evidence of humans in Britain through their tools, Boxgrove (Eartham Quarry) in West Sussex, South England still contains their oldest teeth and bones found so far in this country, which have been dated to Marine Isotope Stage 13, between 525 000 and 478 000 years ago. Prolific finds of flint tools and vertebrate remains (both large and small) have made Boxgrove internationally famous. Microfossils (foraminifera and ostracods), however, have formed the means by which the palaeoenvironment has been reconstructed, and this is narrated here from nearshore marine, through intertidal flats in a semi-enclosed bay to, on final regression, a grassland plain with a series of freshwater pools fed by springs emanating from the Chalk. These pools were the waterholes to which the animals were attracted, and therefore formed the hunting grounds for hominins. Palaeoclimatic reconstructions using the Mutual Ostracod Temperature Range (MOTR) method show that sustained human occupation occurred during a period when the region was colder in winter and may have experienced greater seasonal temperature variation than the present day.