Dorchester Heights turned a maritime lifeline into a trap

The Royal Navy kept Boston supplied for much of the siege, but that access depended on control of the ground overlooking the harbour approaches. Once American heavy guns reached Dorchester Heights, ships could no longer move safely in and out. Britain could have fortified the heights earlier with a permanent work supported from the harbour. Such a fort could have been resupplied by sea and covered by ships firing on an assault. The failure went beyond a shortage of rice: abundant troops, artillery, and naval power were present, but leadership failed to secure the terrain on which maritime access depended.