Much of the importance of the A679 has now been lost since the completion of the M65. It was once part of the Preston-Burnley-Halifax Trunk Road (which itself is now defunct).
Blackburn - Burnley
Blackburn Road, Oswaldtwistle
Since the formation of the A6078 in central Blackburn, the A679 has been rerouted and no longer starts at its original beginning on the A666 at the Darwen Street Bridge junction. It has now been relocated to the junction of Furthergate and Burnley Road (where the A678 originally branched from the A677). Furthergate is now the A678 and therefore the A679 now runs along a former section of the A677 as far as Bank Lane (now B6236) near the Intack traffic lights where the A6119 and B6130 meet. This marks where the former trunk road section (bypassed by motorway in 1984) began. The road continues east along with a 50 mph speed limit past Knuzden. It goes under the M65 without a junction and then into the suburbs of Oswaldtwistle.
The road becomes very built up as it enters Accrington. It is diverted from its original course along Blackburn Road, which is reached by traffic lights. It now runs along the former B6231 to Dunkenhalgh Way, the A6185, and turns right onto Hyndburn Road.
Hyndburn Road feeds traffic into a large roundabout underneath the East Lancashire Line where the A679 becomes Eastgate, part of the town centre's inner relief route. Midway along this road, during a multiplex with the A680, traffic is directed left and the road continues out from Accrington through suburbs until eventually crossing the A56 Accrington eastern bypass at a very compact GSJ. It is here where the road's first 60 mph limit is gained. The road then passes through Hapton and ultimately meets a small link from M65junction 9, where the road briefly gains primary status. A twisty section follows beyond the motorway, now with a 40 mph speed limit (reduced from 60 mph in 2010) through to the traffic lights where the former trunk road (and current primary route) turned right on to the A646 towards Todmorden.
The A679 itself proceeds east, becoming more and more urban - before it reaches the A671 several hundred metres from M65junction 10. At one time the road ended here but there is now a short multiplex east along the A671 - at least that's the number marked on signs here but whether it is the A671 is debatable as it's not called that again. There's a short D2 section past Burnley Barracks station, then the road bears left at traffic lights and is now definitely the A679 again (the road to the right is shown on some maps as the A671 but signs don't give it any number).
Now on the S2Westgate, which is lined with some surprisingly pleasant buildings, the A679 curves round to the right to a roundabout on the edge of Burnley town centre. It turns left here onto the relief road, called Active Way. This is S2 as far as the next roundabout (with a railway viaduct to the left) before becoming D2. This is a typical edge-of-town distributor, with traffic lights giving access to a retail park. The road soon reaches a set of traffic lights where it ends on the A682 (former A56), which is S2 in both directions.