Laysan (; ), located northwest of Honolulu at , is one of the Northwestern Hawaiian Islands. It comprises one land mass of , about in size. It is an atoll of sorts, although the land completely surrounds a shallow central lake some above sea level that has a salinity approximately three times greater than the ocean. Laysan's Hawaiian name, Kauō, means egg. Geology Laysan is the second largest single landmass in the Northwestern Hawaiian Islands, after Sand Island at Midway Atoll. Laysan was created by coral growth and geologic upshift. The fringing reefs surrounding the island cover about . Lake Laysan, the , brown, hypersaline lake in the island's interior, has varied in depth over the decades. In the 1860s, the lake was at most deep, but by the 1920s it averaged deep, because of the buildup of sand that had been blown away in sandstorms. The best way to find fresh water on Laysan is to observe where the finches are drinking; the fresh water floats on the saltier water and accumulates around the shore. The tallest point on the island is at above sea level, on a large dune that covers much of the northern portion of the island. A U.S. Geological Survey study found that Laysan, Midway Atoll, and Pacific islands like them could become inundated and unfit to live on during the 21st century. History Discovery and early expeditions Native Hawaiians may have known about Kauō before Americans and Europeans sailed their ships into the region in the early 19th century (see below). The first reported sightings of the island were by Massachusetts whalers in the 1820s. The Nantucket Enquirer reported a sighting in 1825. Here one probably finds the first reference to the name Laysan in print. They were among many who took advantage of the newly discovered whaling grounds off the coast of Japan, making the waters around the Northwest Hawaiian archipelago an increasingly popular commercial route. A United States government survey of Pacific Ocean geography in 1828 included the earlier whalers' reports and an additional sighting of an island fitting Laysan's description by Capt. "Brigs." This may refer to Capt. John Briggs of New Bedford, who may have come across the island as early as 1822. Various publications name Capt. Stanyukovich of the Russian ship Moller as the discoverer of Laysan. Although he mapped the island in 1828 and attempted to name it