The right-armer is joined by Georgia Elwiss, Sarah Taylor and Danni Wyatt in being awarded full central Contracts, while Linsey Smith - who made her senior debut in the ICC Women's World T20 last November - has been handed a rookie contract.
Twenty-one players are now centrally contracted to ECB - four of those on Rookie Contracts.
Davies said: 'I'm absolutely thrilled to receive my first full contract. It's always been my aim to represent England and this is an exciting step in the right direction. I’m looking forward to continuing the hard work, and the challenge now of getting myself picked.'
The new contracts signify a higher level of remuneration for England Women, continuing the trend since the women's game turned professional in 2014.
The overall salary pot has grown by 10 per cent on 2018, with several players receiving an increase of between 15 and 30 per cent on their 2018 salary. The bonus pot for bi-lateral series wins has also been increased by 25 per cent.
Full retained list:
Tammy Beaumont (Kent)Katherine Brunt (Yorkshire)Kate Cross (Lancashire)Freya Davies (Sussex)Sophie Ecclestone (Lancashire)Georgia Elwiss (Sussex)Jenny Gunn (Warwickshire)Alex Hartley (Lancashire)Amy Jones (Warwickshire)Heather Knight (Berkshire)Laura Marsh (Kent)Nat Sciver (Surrey)Anya Shrubsole (Somerset)Sarah Taylor (Sussex)Fran Wilson (Kent) Lauren Winfield (Yorkshire) Danni Wyatt (Sussex)Alice Davidson-Richards (Kent)*Katie George (Hampshire)* Bryony Smith (Surrey)* Linsey Smith (Sussex)*