Sierra Leone is about 21 times smaller than Alaska.

Alaska is approximately 1,481,348 sq km, while Sierra Leone is approximately 71,740 sq km, making Sierra Leone 4.84% the size of Alaska. Meanwhile, the population of Alaska is ~710,231 people (8.0 million more people live in Sierra Leone).
Tip: This to-scale comparison of Alaska vs. Sierra Leone uses the Mercator projection, which distorts the size of regions near the poles.