One too many of these will do it. Getty Images The holiday season is officially over, and you have one last Sunday to sleep off your hangover before it's back to work in 2015.

To get an idea of where Americans are most likely to be hungover today, we constructed the Business Insider Hangover Index.

Our two main sources were the CDC's 2011 Behavioural Risk Factor Surveillance System (BRFSS), an annual survey of Americans' health habits, and the Census Bureau's 2012 County Business Patterns (CBP) program, which tracks the number and size of businesses in counties and metropolitan areas across the country. A more detailed description of the methodology can be found here.

Once again, the Midwest dominated the list with Ohio and Kansas boasting multiple cities in the top 25. Big cities like San Francisco and Denver also made it onto this year's list.