It's about two-and-a-half times as big as Glacier Bay National Park.
In other words, 31,000,000 dunams is 2.3330 times the size of Glacier Bay National Park, and the size of Glacier Bay National Park is 0.42860 times that amount.(a.k.a. Glacier Bay National Park and Preserve) (Hoonah-Angoon Census area, and Yakutat City and Borough, Alaska)
Containing nine tidewater glaciers, Glacier Bay National Park covers 13,290,000 dunams of which 10,760,000 dunams is designated a Wilderness Area. Glacier Bay is home to the 33.8 km (21 mi) long Margerie Glacier.
It's about two-and-a-half times as big as Sitka.
In other words, 31,000,000 dunams is 2.4680780 times the size of Sitka, and the size of Sitka is 0.40517360 times that amount.(a.k.a. the City and Borough of Sitka) (Alaska)
The second-largest city in both Alaska and the United States, Sitka measures 12,560,380 dunams in total area. The city is known as a major west coast seaport.
It's about two-fifths as big as Lake Superior.
In other words, 31,000,000 dunams is 0.3780 times the size of Lake Superior, and the size of Lake Superior is 2.650 times that amount.(a.k.a. Lac Supérieur, a.k.a. Gitchigumi, a.k.a. Gitche Gumee) (surface area)
Both the largest of North America's Great Lakes and the largest freshwater lake in the world (by surface area), Lake Superior has a total area of 82,100,000 dunams. It borders the cities of Duluth, Minnesota and Thunder Bay, Ontario, Canada
It's about two-fifths as big as South Carolina.
In other words, 31,000,000 dunams is 0.37380050 times the size of South Carolina, and the size of South Carolina is 2.6752240 times that amount.(United States)
The "Palmetto State," South Carolina measures 82,931,940 dunams in total area. South Carolina's border with Georgia is almost entirely marked by the Savannah River, which stretches for 560 km (350 mi) along South Carolina's southeastern boundary.
It's about one-third as big as Maine.
In other words, 31,000,000 dunams is 0.33825870 times the size of Maine, and the size of Maine is 2.9563170 times that amount.(United States)
The "Pine Tree State," Maine measures 91,645,820 dunams in total area. Machias Seal Island, about 80 dunams of Maine's area, continues to be a source of dispute between the United States and Canada, with each country claiming sovereignty over the small, treeless island.
It's about three times as big as Hawaii (Island).
In other words, 31,000,000 dunams is 2.971480 times the size of Hawaii (Island), and the size of Hawaii (Island) is 0.3365330 times that amount.(a.k.a. Hawaii, a.k.a. The Big Island) (Hawaii)
The largest of the main Hawaiian Islands and the largest island in the United States, Hawaii measures 10,432,500 dunams in total area. It is known for its continuously erupting (for the past two decades, as of 2011) volcano, Kīlauea, and for the black sand beaches formed by the lava flow.
It's about one-third as big as Indiana.
In other words, 31,000,000 dunams is 0.32866320 times the size of Indiana, and the size of Indiana is 3.042628 times that amount.(United States)
The "Hoosier State," Indiana measures 94,321,490 dunams in total area. The state is bisected north-south by the Wabash River, one of the longest rivers in the United States at 661 km (411 mi).