The 20-year-old signed for the Magpies last summer from Bristol City Women after helping her former club earn promotion from the Women's Championship.
Boddy was able to repeat that feat last season as she helped Becky Langley's side to the second-tier title, making 22 appearances and scoring twice in all competitions.
She also scored in United's Sela Cup match against AC Milan at St. James' Park in August and played the full 90 minutes in the league-opening 1-1 draw at London City Lionesses on Sunday.
On extending her stay with the club, Boddy said: "I'm buzzing to have signed a new contract at this club. It's the place I want to be and a club I want to excel with, so to sign a long-term contract is very rewarding. I'm so proud, especially being at a club so close to home for me - it's an amazing feeling.
"I feel at home here and, given the way that we play football and the way Newcastle United is as a club, everything here matches my ambitions and that's for the whole club. The desire to win here is huge, so staying here for a long time is exciting."
Manager Becky Langley added: "Elysia is a bright North East talent and she has thrived with us. She was one of the stand-out performers in our first match of the season.
"She is very driven, focused and has an ambitious approach to her training and day-to-day life as a footballer. I'm very hopeful that Elysia and I will share the journey to the WSL and beyond together."