For most Americans, the Census Bureau is like a rabbit that pops out of a hat once every 10 years to ask a few personal questions and then disappears. This mysterious procedure somehow decides how House seats will be allocated among states and  how many federal dollars will flow into each community.

But the Bureau also collects economic and government data and conducts economic and demographic surveys. All this data can offer a treasure trove of information for real estate professionals wanting to improve their marketing strategies or to help homebuyers decide which location is best for them. Best of all, courtesy of Uncle Sam, it doesn't cost a cent – though it might take a professional to figure out how to work with the data to produce what the Bureau calls "a complete and up-to-date profile of neighborhoods with homes for sale."

One of the most important datasets real estate professionals can use is the Longitudinal Employer-Household Dynamics program, especially its Origin-Destination Employment Statistics (LODES) dataset. Another valuable program, On the Map, contains employment data for most states.