Hero's Island (1962) on Netflix

In 1718 a recently freed family of indentured workers inherits the small uninhabited Bull Island off the Carolina coast. The family consist of husband and wife, one son, and a second son who they bought as a baby. The local fishermen who were already using the island think they own the island and attempt to force the family to leave, during which the husband is killed. The conflict over the island escalates as more people including a castaway, a fugitive from justice, and hired heavies join each side. Not everyone is who they seem to be or claim to be.