The smash, involving an overturned animal trailer, happened shortly after 3pm on the A438 north of the town centre. The crash brought traffic to a standstill and tailbacks were as far as the A5 at Chirk.
According to traffic logs, the southbound carriageway of the A438 opened at 5.50pm, but the northbound lane remained shut.
An earlier message, at 5.37pm from Traffic Wales North and Mid said: "#A483 J3 Congestion remains in the area due to ongoing closure. Currently awaiting safe recovery of vehicle."
Motorists were advised to allow additional time for travel.