As of 2017, Crouy-en-Thelle had a population of 1,098, with a population density of 187 per km2.[4] As of 2019, there are 415 dwellings in the commune, of which 399 primary residences.[5]
Crouy-en-Thelle's elevation ranges between 64 m (210 ft) and 137 m (449 ft) above sea level. Its area is 5.87 km2 (2.27 sq mi).[6] The town is 3 km east of Neuilly-en-Thelle, and 8 km northeast of Persan.[7]