The closure will happen at around 6pm for emergency pothole repairs, according to Lincolnshire County Council highways.
The authority says a dangerous pothole has appeared on the A17 near Leadenham. Because of its severity, the emergency highways team are being mobilised to carry out the urgent repair.
In a statement the council said: “Normally, filling potholes would be advertised months in advance - but the nature of this particular pothole is serious enough to warrant a temporary closure of the road this evening.
“The A17 between Sleaford Road and Newark Road will be closed whilst the emergency repair is happening for the safety of the workforce and road users travelling along the busy road in the dark.”