This report describes the excavations of an important British Iron Age centre, whose discovery has transformed current views on the archaeological importance of Lincolnshire. The settlement was characterized by ditched enclosures, perhaps to be interpreted as properties, an irregular pattern of streets, round houses presumably of wood in the Iron Age, and rectangular aisled buildings with stone footings in the Roman period. The inhabitants were engaged in agriculture, stock-keeping, craft or industrial activities and trade. The main occupation was from well before 100 BC to the later 4th century AD or later. Pottery, artefacts and environmental remains are here described and illustrated, providing data for a study of the development of the settlement.