South Dakota is about 12 times smaller than Algeria.

Algeria is approximately 2,381,740 sq km, while South Dakota is approximately 196,540 sq km, making South Dakota 8.25% the size of Algeria. Meanwhile, the population of Algeria is ~44.2 million people (43.4 million fewer people live in South Dakota).
Tip: This to-scale comparison of Algeria vs. South Dakota uses the Mercator projection, which distorts the size of regions near the poles.