Elizabeth McHutcheson Sinclair was a Scottish homemaker, farmer, and plantation owner in New Zealand and Hawaii, best known as the matriarch of the Sinclair family that bought the Hawaiian island of Niʻihau in 1864. Born in Glasgow, Scotland, she married Francis Sinclair, a ship's captain. With six children in tow, the family moved to New Zealand. Her husband and eldest son were later lost at sea.

Niʻihau, anglicized as Niihau, is the westernmost main and seventh largest inhabited island in Hawaii. It is 17.5 miles (28.2 km) southwest of Kauaʻi across the Kaulakahi Channel. Its area is 69.5 square miles (180 km2). Several intermittent playa lakes provide wetland habitats for the Hawaiian coot, the Hawaiian stilt, and the Hawaiian duck. The island is designated as critical habitat for Brighamia insignis, an endemic and endangered species of Hawaiian lobelioid. The United States Census Bureau defines Niʻihau and the neighboring island and State Seabird Sanctuary of Lehua as Census Tract 410 of Kauai County, Hawaii. Its 2000 census population was 160, most of whom are native Hawaiians; its 2010 census population was 170. At the 2020 census, the population had fallen to 84.