Olivia and George have become the new most popular names for babies born in Huntingdonshire.
ONS figures show that 17 newborns were given the name Olivia last year - making it an even more popular girl's name than previous top ranker Emily.
Meanwhile, 22 boys were called George in 2018 - seven fewer than Oliver the year before.
The 610 babies who were called Oliver across the East of England meant it was the most popular boys' name throughout the region, beating George and Harry to top spot.
Olivia was the top East of England girls' name - 527 newborns were handed the moniker by their parents, pushing it to the top of the list, ahead of Amelia and Ava.
Nationally, Oliver also remained the most popular name for boys in England and Wales for the sixth year in a row, ahead of George and Harry.
The ONS data showed Grayson, Rowan and Tobias entered the top 100 names for boys for the first time in 2018.
Olivia topped the girls' list for the third year in succession, with Amelia and Ava in second and third respectively.
Ada, Delilah, Ayla, Zoe, Margot and Felicity entered the top 100 names.
Arthur was the only new entry in the top 10 names for boys in 2018, in seventh, moving Jacob down to 11th. Sophia and Grace, at eighth and 10th respectively, replaced Poppy and Lily in the top 10 names for girls.
Nick Stripe, from the ONS, said: "Oliver and Olivia remained the most popular baby names in 2018, although there are the first signs that Oliver's six-year reign as the number one name for boys is under threat.
"Arthur surged into the top 10 boys' names for the first time since the 1920s, and Ada jumped into the girls' top 100 for the first time in a century too, both perhaps inspired by characters in the BBC TV drama Peaky Blinders.
"On the flip side, the growth in the use of technology assistants in our homes may help to explain why the number of baby girls named Alexa has more than halved compared with 2017.
"Communicating with young children can be hard enough at the best of times."
The top girls' names across the East of England in 2018 were:
1) Olivia: 527
2) Amelia: 477
3) Ava: 365
4) Isla: 363
5) Mia: 327
6) Emily: 304
7) Florence: 283
8) Isabella: 280
9) Sophia: 278
10) Grace: 265
The top boys' names across the East of England in 2018 were:
1) Oliver: 610
2) George: 601
3) Harry: 562
4) Arthur: 480
5) Jack: 473
6) Henry: 441
7) Leo: 410
8) Noah: 406
9) Oscar: 398
10) William: 389