United States is approximately 9,833,517 sq km, while Sierra Leone is approximately 71,740 sq km, making Sierra Leone 0.73% the size of United States. Meanwhile, the population of United States is ~332.6 million people (326.0 million fewer people live in Sierra Leone).
This to-scale map shows a size comparison of United States compared to Sierra Leone. For more details, see an in-depth quality of life comparison of Sierra Leone vs. United States using our country comparison tool.