The A158 at Candlesby in Lincolnshire is closed in both directions between A1028 Baker's Lane/B1196 (Gunby Roundabout) and Chalk Pit Lane due to a large barn fire.
The blaze broke out at around 7.45am. Fire crews are at the scene. Police have advised the road will be closed for most of the day.
There are reports of delays and congestion. Traffic is being affected between Skegness and Horncastle.