Administrative borders are arbitrary and rarely have anything to do with the actual borders of the city. Population density figures should be reported as avera

Administrative borders are arbitrary and rarely have anything to do with the actual borders of the city. Population density figures should be reported as averages over people rather than averages over land. They are usually not, because it's difficult to calculate them that way. If you have a residential area with 20k people in a square mile next to an undeveloped square mile, the population density is usually reported as 10k people / square mile. But from the perspective of the people living there, as well as for the purposes of infrastructure construction, the actual population density is closer to 20k people / square mile.