The chart below shows the population of Mortlake parish from 1801 to 2021 based on census figures. Until 1893 the parish included a substantial area of Kew. The precise boundary of the parish before and after the change is shown here.

The light blue columns show the population including the Kew area. The darker blue columns show the population excluding the Kew area. For 1891 and 1901 the figures are available on both bases.

From 1801 to 1951 Mortlake parish is identified in the census reports. From 1961 the population of Mortlke is estimated from ward or small area statistics in the way explained here.