Kylie Jenner continued her 21st birthday celebrations in Las Vegas over the weekend.

The 'Keeping Up With The Kardashians' star jetted off to Nevada with her friends Jordyn Woods, Tiffany Sorya, Stassi Karanikolaou, Yris Palmer and assistant Victoria Villarroel to mark the milestone birthday.

The group were spotted partying into the early hours of Sunday morning after Kylie's partner Travis Scott performed at the Marquee in Las Vegas, E! News reports.

It comes after a source revealed Kylie is ''very proud'' of what she's accomplished at a young age, after being named one of America's richest self-made women by Forbes magazine last month.

An insider said: ''[Kylie] is very proud that she is only 21 and has accomplished so much already. She says the best thing to happen to her is Stormi. She is crazy about her little girl. She gets a bit emotional thinking back about everything amazing that has happened this year.''

Kylie celebrated her birthday in style earlier this week, but hosted a smaller celebration at home with her tot for company.

The insider added: ''She had a smaller birthday celebration at home with Stormi. She just loves being her mom.''

The blonde beauty kicked off her birthday celebrations with her family and friends - including mother Kris Jenner, and sisters Kim Kardashian West, Kourtney and Khloe Kardashian, and Kendall Jenner - with a dinner at Craig's in West Hollywood.

The group then headed off to nearby nightclub Delilah, which had been decked out with floral arrangements and a ball pit set up in the back room. Guests could choose their cup colour depending on their relationship status - red for taken, yellow for single and green for it's complicated.

A source said: ''People were having fun choosing and were messing around. All of the girls were drinking together. Everyone was letting lose and having a great time. Even Kim was drinking and everyone was surprised.''