Hi Maura,
Thank you for posting in Microsoft Community.
The location shown under Devices at account.microsoft.com is based on your IP address, which can be inaccurate especially if your ISP routes traffic through a distant hub like Rancho La Costa, CA. In contrast, the Sign-in activity map uses more precise data like GPS or Wi-Fi, which explains the correct location there.
To improve accuracy, enable Location Services in Windows settings and set a default location in the Maps app. You can also try renaming your Wi-Fi SSID temporarily (e.g., add _optout), disable any VPNs, and restart your router to refresh your IP.
While you can't manually clear the incorrect location, removing and re-adding the device or switching briefly to a local account may help reset it.
I hope you find this information helpful. Please let me know if you have any further questions If the answer is helpful, please click "Accept Answer".
Regards,
Carlo