According to recent research mapping sentiment on Twitter, Napa - located in the heart of California's Wine Country region - is home to the happiest tweeters in the nation.

California as a whole, however, did not even rank in the top five in a measure of happiness on Twitter. Figure 1. Average word happiness for geotagged tweets in all US states collected during calendar year 2011, from PLoS ONE

In Figure 1, the redder the state, the happier the tweets. Using geotagged tweets, researchers at the Vermont Complex Systems Center analyzed keywords used throughout 2011 in conjunction with annually surveyed characteristics of all 50 states to conclude that the happiest Tweeters come from Hawaii, Maine, Nevada, Utah and Vermont. Reversely, the saddest states are Louisiana, Mississippi, Maryland, Delaware and Georgia - with Beaumont, Texas ranking as the saddest city in America.

"The differences in the words people used told us a lot about the cities themselves," lead author Lewis Mitchell said. "Essentially we were able to create a geography of happiness."

While the research provides a colorful map of happiness throughout the nation, the goal of the year long analysis was to "investigate how geographic place correlates with and potentially influences societal levels of happiness."

Focusing on the impact of urban living on well-being, researchers analyzed words within tweets based on a happiness level, identifying curse words as a key indicator of unhappiness.

With only 15% of adults on Twitter and only 10% of tweets collected, it's important to note that the study represents a subset of the population and should not be used to define the behavior of the population as a whole. Furthermore, the "happiest" locations are also known vacation spots, making the geographical correlation tainted.

Read the full report here or follow @geographyofhapp for daily updates on the geography of happiness on Twitter.

Do you think we can measure happiness on Twitter?