Polynesian explorers from the Marquesas Islands or Society Islands may have arrived in Kauaʻi, initiating the settlement of the Hawaiian islands. Later analyses suggest a later arrival time.

British navigator James Cook made the first recorded European contact with the Hawaiian Islands when he arrived at Kauaʻi by accident during his third voyage of exploration. The British observed similarities in language and culture between the Kauaians and other parts of Polynesia.

Kamehameha I, king of Hawaii Island, had established the Kingdom of Hawaii, uniting most of the islands, but Kauaʻi remained independent.

Kamehameha I's attack from Oahu was canceled due to stormy seas, and he was afterward distracted by events elsewhere.

Kaumualiʻi ruled Kauaʻi and maintained its independence from the Kingdom of Hawaii.

A second invasion of Kauaʻi from Oahu was planned but canceled after an epidemic broke out among Kamehameha's forces.

Kaumualiʻi agreed to be Kamehameha's vassal and to cede Kauaʻi to the Kingdom of Hawaiʻi upon his death by making Kamehameha's son his heir.

Georg Anton Schäffer, working with the Russian American Company, instigated a diplomatic episode involving Kaumualiʻi. Kauaʻi would accept the protection of the Russian Empire in exchange for exclusive trading privileges.

A fort was built at Waimea and a Russian flag raised over it.

Kaumualiʻi abandoned his relationship with Schäffer and forced the Russians to leave Kauaʻi, persuaded by Kamehameha's orders and other foreign traders.

The first sugarcane plantation was founded on Kauaʻi, marking the beginning of an industry that would dominate Hawaiʻi's economy for the next century.

Old Koloa Town opened a sugar mill, contributing to the growth of the sugarcane industry on Kauaʻi.

Valdemar Emil Knudsen, a Norwegian, arrived on Kauaʻi and later became a successful sugarcane plantation owner and influential politician.

John Mahiʻai Kāneakua held the office of County Clerk and was active in attempts to restore Queen Liliuokalani to the throne after the U.S. takeover of Hawaiʻi in 1893.

John Mahiʻai Kāneakua held the office of County Clerk and was active in attempts to restore Queen Liliuokalani to the throne after the U.S. takeover of Hawaiʻi in 1893.

A rain gauge at Kauaʻi's former Kilauea Sugar Plantation recorded a record twelve inches of precipitation in just 60 minutes during a storm.

The average yearly precipitation was 460 in (11,700 mm) at Mt. Waiʻaleʻale based on data for the period from 1931 through 1960.

The Kauaʻi Island Utility Cooperative burned sugarcane waste to supply most of its electricity.

A record low temperature of 29 °F (−2 °C) was recorded at Kanaloahuluhulu Meadow in Kōkeʻe State Park.

The Kauaʻi Heritage Center of Hawaiʻian Culture and the Arts was founded to nurture appreciation and respect for Hawaiian culture.

Disney's animated feature film Lilo & Stitch was released, featuring Kauaʻi.

1,271,000 people visited Kauaʻi, with the majority from the continental United States and Japan.

Kauaʻi's last sugarcane plantation, the Gay & Robinson Plantation, stopped planting sugar after 118 years.

KIUC's fuel mix was 56% fossil fuels, 9% hydroelectric, 12% biomass and 23% solar.

KIUC opened a Tesla Energy 13 MW / 52 MWh battery next to the 12 MW Kapaia solar plant for 13.9¢/kWh.

KIUC opened an AES Distributed Energy project for 20 MW solar with 20 MW / 100 MWh batteries priced at 11.1¢/kWh.

The island's population was recorded at 73,298.