Those are in:

• VA house of delegates district 26 (in parts of Loudoun County)
• VA senate district 32 (in parts of Loudoun County)
• VA senate district 10 (in parts of many countries around central VA)

You can see the district outlines at the link above or find your state legislature districts at

https://whosmy.virginiageneralassembly.gov/

Early voting both in-person and by mail has already started in the first two in Loudoun County! Early in-person voting will start in the 10th senate district on December 27th