Alaska is about 21 times bigger than Sierra Leone.

Sierra Leone is approximately 71,740 sq km, while Alaska is approximately 1,481,348 sq km, making Alaska 1,965% larger than Sierra Leone. Meanwhile, the population of Sierra Leone is ~8.7 million people (8.0 million fewer people live in Alaska).
Tip: This to-scale comparison of Sierra Leone vs. Alaska uses the Mercator projection, which distorts the size of regions near the poles.