It took three hours for the road to fully reopen between junctions seven and eight following the incident at around 5pm.
A vehicle pulling a trailer carrying two tractors lost control and overturned, blocking lane one. There were not thought to be any serious injuries.
Although there was only one lane of three closed, traffic was at a standstill between J3 and J8 eastbound for most of rush hour and motorists trying to find an easier route home also clogged up major roads around Kettering.
The Highways Agency said the incident had been dealt with at just after 8pm.