The Year of the Dome is the unspecified year in which the events from Under the Dome (the novel) happen, which is generally assumed to be 2012. The novel doesn't expressly state which year it is when the dome comes down, but there is evidence provided to make an estimate. There is mention of a bumper sticker to re-elect President Barack Obama, and, since he was up for re-election in 2012, the novel had to take place either on or after 2012. Given that the bumper sticker was faded (although presumably still legible), it's arguable that the dome came down in 2013 or 2014 although it could also be 2017, seeing as the next year after 2012 with the same days and dates is 2017, if thought about logically. The previous year to have those exact same days and dates was 2006, 10 years ago.