A Wyoming King is more than just a giant family mattress. A Wyoming King is an oversize mattress that can improve your sleep at night. Sprawling out across such a wide king-size bed is a luxury that can't be matched. While it's a size that works well for families, a single sleeper or partners will love a bed this much bigger than a standard king. The Wyoming King is the largest king-size mattress available, which means it's the most luxurious option, too - perfect for sleepers of all kinds.