The population of Britain in 2021 was over six times the population in 1801, so the country's overall population density was also six times higher. This is difficult to map because the density bands used in the maps have to change over time, and the bottom four bands in 1801 all fit into the bottom 2011 band. Although the mountains of Scotland and Wales still contain few people, rural England has become much more crowded. Historically much of the population was concentrated into quite small urban areas that hardly show up on the maps. In towns where the main way of getting about was walking, extreme crowding was inevitable, but urban areas expanded with the growth of alternative means of transport.

Note that our figures for the area of units as measured in hectares have always been calculated by us from our boundary maps, while all areas measured in acres are figures that were listed in census reports.