Delaware is around the same size as Brunei.

Brunei is approximately 5,765 sq km, while Delaware is approximately 5,060 sq km, making Delaware 87.77% the size of Brunei. Meanwhile, the population of Brunei is ~478,054 people (419,880 more people live in Delaware).
Tip: This to-scale comparison of Brunei vs. Delaware uses the Mercator projection, which distorts the size of regions near the poles.