According to NOAA’s article, Assessing the U.S. Climate in 2017, it was the third hottest year on record for the U.S. It also wasn’t an El Nino year. In summary,
This was the third warmest year since record keeping began in 1895, behind 2012 (55.3°F) and 2016 (54.9°F), and the 21st consecutive warmer-than-average year for the U.S. (1997 through 2017). The five warmest years on record for the contiguous U.S. have all occurred since 2006.
For the third consecutive year, every state across the contiguous U.S. and Alaska had an above-average annual temperature. Despite cold seasons in various regions throughout the year, above-average temperatures, often record breaking, during other parts of the year more than offset any seasonal cool conditions.
The article has other useful graphs and information, including a summary for December. Related data is linked to their Climatological Rankings page.