How Many Blocks from NYC's Southern Tip to Its Northern Peak? ~8,580

The straight-line distance from Fort Wadsworth (Staten Island, southernmost) to Inwood Hill Park (Manhattan, northernmost) is ~33 miles (53 km). Using the common estimate of 260 city blocks per mile (Manhattan grid), that yields ~8,580 blocks. Note: blocks vary in length (especially crosstown), and the route isn't a straight grid line—this is a rough heuristic.