Mill Levy Laws in Kansas | Legal - what is a mill levy ,A mill levy, also known as a millage rate, is an alternate term for a property tax rate. Mill levies, when multiplied by the value of the property being taxed, provide a property's annual tax liability.Historic Mill Levies - Douglas County GovernmentThe files listed below show the historic mill levies for all taxing authorities in Douglas County from 1966 through the current year.