Petty’s Down Survey shows how mapping transformed military conquest into an administrative mechanism, turning land, livelihoods and inherited claims into measurable assets for redistribution. The article highlights an enduring tension: these maps preserve valuable evidence about places and former owners, yet they also helped make Catholic dispossession more enforceable and Protestant ownership more secure. Henry Cromwell’s cautious administration further suggests that orderly governance depended upon fragile military and political support after Oliver Cromwell’s death. How should historians and communities interpret the Down Survey as both an archive and instrument of settlement, especially when considering its long-term effects on Irish landownership?