Census: American Community Survey
These data files contain the most recent (but not the most reliable) estimates of population characteristics.
For the most recent estimates (at the city level only), choose 2012 ACS 1-year estimates.
For a set of estimates that are more reliable (smaller confidence intervals), and include more variables, choose the 2010-2012 ACS 3-year or the 2008-2012 ACS 5-year estimates. The 5-year estimates may be searched the census tract and block group level.