The short answer to this is that the median household income in the United States for the period from 2009 to 2013 was $53,046. The source for this answer is found in the link below. This is information from the US Census Bureau, which compiles and publishes many statistics about the United States.
In order to understand what this means, we need to understand that a median is different from a mean. The median household income in the US is the income that is exactly halfway through the distribution. In other words, exactly half of the households in the US have a higher income than this and exactly half have a lower income. This can differ significantly from the mean (average) household income because the mean can be affected by outliers while the median cannot.