Example methods and apparatus for associating media devices with a demographic composition of a geographic area are disclosed. A disclosed example method includes receiving a plurality of Internet Protocol addresses assigned to a media device associated with a panel member, determining a most used Internet Protocol address from the plurality of Internet Protocol addresses, accessing geographic information and determining a geographic location corresponding to the most used Internet Protocol address, accessing demographic information and determining a demographic profile associated with the geographic location, and associating at least one of the geographic location or the demographic profile with the media device.