Belmont at least has some density and Main Street. Atherton’s density is 1/4 of Belmont’s and it occupied the very center of SV.

Atherton 1,438.97/sq mi (555.53/km2)

Belmont 5,843.98/sq mi (2,256.45/km2)

San Mateo 8,570.40/sq mi (3,309.14/km2)