Jersey is about 1.5 times smaller than District of Columbia.

District of Columbia is approximately 177 sq km, while Jersey is approximately 116 sq km, making Jersey 65.54% the size of District of Columbia. Meanwhile, the population of District of Columbia is ~601,723 people (499,577 fewer people live in Jersey).
Tip: This to-scale comparison of District of Columbia vs. Jersey uses the Mercator projection, which distorts the size of regions near the poles.