1801 - 864,845
1811 - 1,009,546
1821 - 1,225,694
1831 - 1,474,069
1841 - 1,870,727
1851 - 2,362,236
1861 - 2,803, 921
1871 - 3,300,000

But, taking the population of the four counties in which London stands, we shall arrive at a number perfectly Chinese in its density; and when we come to consider that, according to the income-tax returns, three-fourths of those paying the tax in the metropolitan districts are living on incomes of less than £300 and the great mass on less than £100 a year, we shall arrive at a fair approximation of the industrial character of the inhabitants.

Routledge's Popular Guide to London, [c.1873]

Area and Population 1896

London, within the Registrar-General's Tables of Mortality - 116¾ sq. Miles - 4,411,710 population
Administrative County of London - 117¼ sq. Miles - 4,433,018 population
London School Board District - 117¼ sq. Miles - 4,433,018 population
Metropolitan Parliamentary Boroughs - 117¼ sq. Miles - 4,433,018 population
The "Greater London" of the Registrar General's Weekly Return - 693 sq. miles - 5,633,806 population
    Consisting of-
        (a) Metropolitan Police District - 692 sq. miles - 5,596,101 population *(These figures are for 1891, the latest that are available)
        (b) City of London, within the Municipal and Parliamentary limits - 1 sq. miles - 31,148 *(These figures are for 1891, the latest that are available)
    The figures for the City represent the night population; during the business hours of the day it rises to over 1,000,000. "Greater London" estimated (1897), 6,291,677.
    The population of London in 1801 was 958,863; in 1811, 1,138,815; in 1821, 1,378,947; in 1831, 1,164,994; in 1841, 1,948,369; in 1851, 2,362,236; in 1861, 2,803,989; in 1871, 3,254,260; in 1881, 3,816,483; in 1891, 4,231,431. The annual rate of increase of population since 1801 has thus been about 36,000, and during the last decennial period about 40,000 persons against 56,000 in the previous period, 1871-81.

J.G. Bartholomew, The Pocket Atlas and Guide to London, 1899