[CTPP] Census population density calculations

Hello all, I am finding discrepancies between population densities that I'm calculating in ArcGIS using Census 2010 population data and the TIGER geography shapefiles (in my case for the county and state level), and population density numbers posted on Census websites. The discrepancy is from the square mileage calculation, in particular. Does anyone know if this is because water bodies are subtracted from the total square mileage for the density calculation (or if there is another reason for the discrepancy)? Thank you, Elizabeth Elizabeth Hassett Syracuse Metropolitan Transportation Council 100 Clinton Square 126 N. Salina Street, Suite 100 Syracuse, NY 13202 ehassett(a)smtcmpo.org (P) 315-422-5716 (F) 315-422-7753 Elizabeth Hassett Syracuse Metropolitan Transportation Council 100 Clinton Square 126 N. Salina Street, Suite 100 Syracuse, NY 13202 ehassett(a)smtcmpo.org (P) 315-422-5716 (F) 315-422-7753