Our knowledge of the Earth's magnetic field intensity changes over the past few thousand years is still limited because of the uneven spatial and temporal distribution of data, which also includes the Americas. The present study reports 41 new palaeointensity data covering the past 3600 years which, together with 38 previously published data of similar quality, are used to construct a palaeointensity secular variation curve for Central Mexico. These new data are an important contribution to the global intensity database and will also improve the application of palaeomagnetic dating in Mexico, which is of interest because of the many Holocene monogenetic volcanoes within the Trans-Mexican Volcanic Belt, and of its archaeological heritage. The most conspicuous feature of the new intensity curve is the rapid increase between 400 and 250 BCE, from about 45 to 65 μT. Other relative intensity highs of ≈45–55 μT …