Archaeological excavations in advance of an extensive development at Littlehampton,on the West Sussex coastal plain, examined part of a large multi-period settlement complex comprising deposits principally of later Bronze Age, Iron Age and Roman dates. One large site north of Toddington Lane and one smaller site to its south were investigated in ten areas based on the results of earlier evaluation, but it is clear that a substantial contiguous settlement complex that had extended for more than 400m had been extensively truncated by previous development on the sites. The Bronze Age deposits included a possible ritual shaft, and for the coastal plain, a rarely encountered ring ditch. The later Bronze Age is also notable for the presence of a field system. Evidence for Middle Iron Age occupation is relatively slight, lacking classic ring-gully houses but mainly represented by enclosure ditches. The majority of the features at both sites belong to the Late Iron Age into Roman period and comprise a complex farmstead. The settlement seemingly flourished until abandonment in the later 2nd or early 3rd century, well before the traditional end of Roman Britain, which is an increasingly observed pattern for sites on the coastal plain. Indeed, the smaller, southern site was abandoned even before this. Apart from farming, the site was not occupied again until the construction of horticultural nurseries in the 20th century. Both sites provided substantial pottery assemblages, and the prehistoric chronology is supported by nine radiocarbon dates. Among the other finds, the number of quern stones is notable.