Eventually, he left New York. Lawson visited Florida when he befriended Katherine and Royce Powell, his close friends and patrons who lived there. He first stayed with them in Coral Gables in 1931, and he returned there often, moving permanently to Florida in 1936. In his last years, he completed a post office mural in Short Hills, New Jersey (no longer extant), but he focused primarily on painting the Florida landscape. Depressed and in declining health, he drowned under mysterious circumstances in 1939, apparently while swimming on Miami Beach. Friends wondered if Lawson's death had been a suicide.