Selby is a city in Walworth County, South Dakota, United States.

[6] Selby sprang up with the arrival of the Chicago, Milwaukee, St. Paul and Pacific Railroad to the area in 1899.

[7] According to the United States Census Bureau, the city has a total area of 0.71 square miles (1.84 km2), all land.

There were 334 housing units at an average density of 470.4 per square mile (181.6/km2).

The racial makup of the city was 96.7% White, 2.0% Native American, and 1.2% from two or more races.

There were 335 housing units at an average density of 401.8 per square mile (155.1/km2).