Bristol and North Somerset will move from Tier 3 to Tier 2 from Saturday.
And Herefordshire will go into Tier 1, Health Secretary Matt Hancock said.
Mr Hancock said the “vast majority” of places in England’s Tier 3 restrictions will not be changed, but added in the Commons: “In Bristol and North Somerset rates have come down from 432 per 100,000 to 121 and falling.
“Bristol and North Somerset will come out of Tier 3 into Tier 2 on Saturday.
“Rates in Herefordshire have also come down to 45 in 100,000 and are falling, and we can therefore bring Herefordshire out of Tier 2 and into Tier 1.”
But large swathes of southern England will be placed under Tier 3 restrictions because of rising coronavirus levels.
A total of 38 million people will be living in Tier 3 of the Government’s Covid-19 restrictions from this Saturday – 68% of the population of England.
Some 30% of the population will be in Tier 2 while 2% will be in Tier 1.
The changes will take effect from 0001 on Saturday.
Mr Hancock said areas moving into Tier 3 are: Bedfordshire, Buckinghamshire, Berkshire, Peterborough, the whole of Hertfordshire, Surrey with the exception of Waverley, Hastings and Rother on the Kent border of East Sussex, and Portsmouth, Gosport and Havant in Hampshire.
Mr Hancock said the UK has “come so far” and “mustn’t blow it now”.
Making a statement in the Commons, he told MPs: “As we enter the coldest months we must be vigilant and keep this virus under control.”
Matt Hancock said he “regrets” moving more areas into Tier 3 but that it is “necessary”.
He told the Commons: “I regret having to take the action that we have to take.
“I deem it necessary and there is a strong view right across Government that these actions are necessary.
“But I also plead that personal responsibility is absolutely essential to how we as a society should respond to this pandemic.”
The cautious approach comes amid mounting concern about the prospect of a surge in cases following the easing of restrictions over the Christmas period.
Matt Hancock said the three-household Christmas bubble rule is “not a limit up to which we should all push”.
Conservative chairman of the Health and Social Care Select Committee Jeremy Hunt said: “I want to ask him about Christmas, just a week away. Of course personal responsibility matters, but in a pandemic so does clarity.
“So irrespective of the law or the regulations, should we or should we not have indoor social gatherings with elderly and vulnerable family members?”
Mr Hancock replied: “People should act with great caution. People should act with great caution in this pandemic because it protects them, it protects their families, it protects their loved ones.
“We’ve set out what the rules are but they are not a limit up to which we should all push. We can all act within those rules to limit the spread.
“And by reducing social contact in the days up to meeting a family member who may be, for instance, over 70, or any other family member, it is reasonable and responsible to take that sort of action.”