Kamehameha I (Hawaiian pronunciation: [kəmehəˈmɛhə]; Kalani Paiʻea Wohi o Kaleikini Kealiʻikui Kamehameha o ʻIolani i Kaiwikapu kauʻi Ka Liholiho Kūnuiākea; c. 1736 – c. 1761 to May 8 or 14, 1819), also known as Kamehameha the Great, was the conqueror and first ruler of the Kingdom of Hawaii. The state of Hawaii gave a statue of him to the National Statuary Hall Collection in Washington, D.C., as one of two statues it is entitled to install there.

Kamehameha (known as Paiʻea at birth), was born to Kekuʻiapoiwa II, the niece of Alapainui, the usurping ruler of Hawaii Island who had killed the two legitimate heirs of Keaweʻīkekahialiʻiokamoku during civil war. By most accounts, he was born in Ainakea, Kohala, Hawaii. His father was Keōua Kalanikupuapa'ikalaninui; however, Native Hawaiian historian Samuel Kamakau says that Maui monarch Kahekili II had hānai adopted (traditional, informal adoption) Kamehameha at birth, as was the custom of the time. Kamakau believes this is why Kahekili II is often referred to as Kamehameha's father. The author also says that Kameʻeiamoku told Kamehameha I that he was the son of Kahekili II, saying, "I have something to tell you: Ka-hekili was your father, you were not Keoua's son. Here are the tokens that you are the son of Ka-hekili."

King Kalākaua wrote that these rumors were scandals and should be dismissed as the offspring of hatred and jealousies of later years. Regardless of the rumors, Kamehameha was a descendant of Keawe through his mother Kekuʻiapoiwa II; Keōua acknowledged him as his son and he is recognized as such by all the sovereigns and most genealogists.

Accounts of Kamehameha I's birth vary, but sources place his birth between 1736 and 1761, with historian Ralph Simpson Kuykendall believing it to be between 1748 and 1761. An early source is thought to imply a 1758 dating because that date matched a visit from Halley's Comet, and would make him close to the age that Francisco de Paula Marín estimated he was. This dating, however, does not accord with the details of many well-known accounts of his life, such as his fighting as a warrior with his uncle, Kalaniʻōpuʻu, or his being of age to father his first children by that time. The 1758 dating also places his birth after the death of his father.

Kamakau published an account in the Ka Nupepa Kuokoa in 1867 placing the date of Kamehameha's birth around 1736. He wrote, "It was during the time of the warfare among the chiefs of [the island of] Hawaii which followed the death of Keawe, chief over the whole island (Ke-awe-i-kekahi-aliʻi-o-ka-moku) that Kamehameha I was born". However, his general dating has been challenged as twenty years too early, related to disputes over Kamakau's inaccuracy of dating compared to accounts of foreign visitors. Regardless, Abraham Fornander wrote in his book, An Account of the Polynesian Race: Its Origins and Migrations: "when Kamehameha died in 1819 he was past eighty years old. His birth would thus fall between 1736 and 1740, probably nearer the former than the latter". A Brief History of the Hawaiian People by William De Witt Alexander lists the birth date in the "Chronological Table of Events of Hawaiian History" as 1736. In 1888 the Kamakau account was challenged by Samuel C. Damon in the missionary publication; The Friend, deferring to a 1753 dating that was the first mentioned by James Jackson Jarves. But the Kamakau dating was widely accepted due to support from Abraham Fornander.

At the time of Kamehameha's birth, his father, Keōua, along with his half-brother, Kalaniʻōpuʻu, were serving Alapaʻinui, ruler of the island of Hawaiʻi; Alapaʻinui had brought the brothers to his court, after defeating both of their fathers in the civil war that followed the death of Keaweʻīkekahialiʻiokamoku. Keōua had died while Kamehameha was very young, thus the boy was raised in the court of his uncle, Kalaniʻōpuʻu. The traditional mele chant of Keakamahana (chiefess and wife of Alapainui) mentions that Kamehameha was born in the month of ikuwā (autumn/winter), or around November; Alapai gave the young Kamehameha to Keaka and her sister, Hākau, to raise, once the ruler discovered the infant had indeed survived.

On February 10, 1911, the Kamakau version was challenged by the oral history of the Kaha family, as published in newspaper articles also appearing in the Kuoko. After Kamakau's history was published again (this time to a wider, English-reading public in 1911 Hawaii), the Kaha version of these events was published by Kamaka Stillman, who had objected to the Nupepa article.

Kamehameha was raised in the royal court of his uncle Kalaniʻōpuʻu. He achieved prominence in 1782, upon Kalaniʻōpuʻu's death. While the kingship was inherited by Kīwalaʻō, Kalaniʻōpuʻu's son, Kamehameha was given a prominent religious position as guardian of the Hawaiian god of war, Kūkaʻilimoku. He was also given control of the district of Waipiʻo Valley. The two cousins' relationship was strained after Kamehameha made a dedication to the gods instead of allowing Kīwalaʻō to do that. Kamehameha accepted the allegiance of a group of chiefs from the Kona district.