As of 2003, the city had an estimated population of 84,145 and a population density of 2,345.83 persons per km². The total area was 35.87 km².
As of October 1, 2005, Kōnosu absorbed the town of Fukiage (from Kitaadachi District), and the town of Kawasato (from Kitasaitama District) to create the current and expanded city of Kōnosu. As of 2010, Kōnosu's population increased to 119,831 and the total area is now 67.49 km², with a population density of 1,780 persons per km².
Kōnosu earned the nickname "Doll Town" for its many "Hina Ningyou" (a type of Japanese doll) factories. Kōnosu is also called "Flower town". It has several flower markets, and many flowers purchased in Tokyo and Kantō region are grown in Kōnosu. The most popular flower in the city is the pansy, which is also the city's official flower.