The package was discovered near the Muller yoghurt factory in Market Drayton, Shropshire.
West Mercia Pigs tweeted that bomb disposal experts from the Explosive Ordnance Disposal were on their way at 10:13pm.
A 100m cordon has been put in place on the A53 from the Muller Roundabout to the Tern Hill Roundabout.
The nearby McDonald’s has been cosed and people are being asked to avoid the area.
@WMerciaPolice tweeted: “We are currently in attendance at the Muller site in #MarketDrayton, #Shropshire after a suspicious package was discovered.
“Bomb disposal experts from Explosive Ordnance Disposal (EOD) have been informed and will arrive at the site shortly.
“A 100m cordon has been put in place on the A53 from the Muller Roundabout to the Tern Hill Roundabout and the McDonalds nearby has been closed.
“People are asked to avoid the area and seek alternative routes.”