This thesis provides a comprehensive digital catalogue and assessment of early medieval castles in the Kingdom of England from the eleventh to thirteenth century CE. Recently released LIDAR-based terrain models are used to measure archaeological castle site features alongside data for historical settlement locations, navigable rivers, and other spatial elements to reassesses the potential economic functions and influence of castles within the developing manorial landscape. Previous research within English castle studies has often focussed on the military and architectural elements of archaeological sites, sometimes to the detriment of their greater context and complexity. Within recent decades, lordly administrative and residential functions, display of conspicuous consumption and prestige, spatial delineation of hierarchical power structures, and economic orientation within the intricately ordered social and built landscapes have become more widely recognised in castle interpretation. This research expands on and tests recently theorised economic functions of castles through the simultaneous analysis of the broader settlement network within which they functioned, identifying ways in which castle and settlement patterns influenced each other. The GIS-based analyses demonstrate not only that the eleventh century settlement pattern impacted the subsequent distribution pattern and typological nature of introduced castles, but also that this newly established pattern of castle sites went on to structure significant aspects of the twelfth and thirteenth century settlement distribution, producing a uniquely English urban network arrangement. The results further suggest that the locational choice, usage dates, and site plans of early castles need to be understood in the context of the underlying economic landscape within which they were constructed and went on to reorient and manipulate.