In 1875 Trousseau bought a large tract of land in present-day Honalo on the island of Hawaiʻi, and moved there in 1877. His plan was to raise sheep on high pasture land. A road still named for him is still visible at , which once ran about from the Puʻulehua ranch at elevation on the slopes of Mauna Loa to the beach. He also entered into a relationship with a Hawaiian woman Makanoe, who was already married.