Lake Tahoe is around the same size as Flathead Lake.

Flathead Lake is approximately 510 km² (197 sq mi), while Lake Tahoe is approximately 502 km² (194 sq mi), making Lake Tahoe 98.43% the size of Flathead Lake.
Tip: This to-scale comparison of Flathead Lake vs. Lake Tahoe uses the Mercator projection, which distorts the size of regions near the poles.
Our free app, MapSize by MyLifeElsewhere — compare any two places, to scale on your mobile device.