Towns including Blackpool, Blackburn and Fleetwood will be subject to the strictest measures, alongside the Liverpool City Region which has had measures in place since Wednesday (14 October).
Under the harshest tier, an area is categorised as at a “very high” alert and residents are banned from socialising with other households in any setting.
Pubs and bars will be told to shutter unless they can serve substantial meals with alcohol.
However, gyms and beauty salons can remain open in Lancashire, it has been widely reported.
Lancashire council has confirmed a deal on further economic support has been reached to the media – but the central Government has not issued any details on their end just yet.
Geoff Driver, leader of Lancashire County Council, told the BBC he felt there was a "good deal" for the region.
He said there was a package worth £42m, with £30m to help businesses including pubs affected.
The Government confirmed the restrictions would come into effect tomorrow. They will be reviewed every two weeks.
A statement from the Department of Health and Social Care said: "Following close discussions with local leaders, Lancashire will move from Local COVID Alert Level High to Very High from 00.01 on Saturday 17 October."
Some 1,144 pubs and bars will be affected by this announcement, according to real estate adviser Altus Group.
It comes as discussions over Greater Manchester’s alert level stalled without resolution this week after city leaders said businesses needed more financial support.
Several areas moved up to tier 2 yesterday - including London, Essex, Elmbridge, Barrow-in-Furness, North East Derbyshire, Erewash, Chesterfield, and York.
The changes were announced by Health Secretary Matt Hancock in the House of Commons and will come into effect on Saturday 17 October.