Of the applications submitted on April 20, more than two-thirds were by people aged 34 and under.
Applications to register to vote jumped sharply on Monday – the final day to apply ahead of the elections taking place in England, Scotland and Wales on May 7.
Some 112,641 applications were submitted, up from 42,827 on Sunday and comfortably the highest number on a single day so far this year, Government figures show.
People had until 11.59pm on April 20 to register to vote.
Elections are being held on May 7 to choose members of the Scottish Parliament and the Senedd in Wales, while some 5,013 council seats in England are up for grabs across 136 local authorities.
There are also contests to choose six local mayors.
Members of the Scottish Parliament and the Senedd were last elected in 2021, while this is the largest set of local elections in England for three years.
Of the applications submitted on Monday, more than two-thirds were by people under the age of 35, with 39% from those under 25 and 28% from 25 to 34-year-olds.
Some 14% of applications were from 35 to 44-year-olds, 8% from 45 to 54-year-olds, 6% from 55 to 64-year-olds, 3% from 65 to 74-year-olds and 2% from people aged 75 and over.
Applying to register to vote is not the same as being registered to vote.
The latest figures are likely to include instances of people submitting an application who are already on the electoral register or who are ineligible to vote.
There is a separate deadline of 5pm on Tuesday April 21 to apply for a postal vote in the elections.
Applications can be made online at gov.uk/apply-postal-vote.
All voters in England intending to cast a ballot in the elections on May 7 will not only need to be registered but also show a form of photo identification at the polling station.
Not all types of photo ID will be accepted, but a passport, driving licence or blue badge are valid.
Anyone without the correct identification will need to apply for a voter authority certificate by 5pm on Tuesday April 28, which can be done online at gov.uk/apply-for-photo-id-voter-authority-certificate.
Photo ID is not needed to vote in the elections for the Scottish Parliament or Senedd.
April 28 is also the deadline to apply for a proxy vote, to allow someone to vote at a polling station on your behalf.
Applications can be made online at gov.uk/apply-proxy-vote.
