The district is entirely on the island of Oahu, encompassing the urban areas of the City and County of Honolulu, a consolidated city-county that includes Oahu's central plains and southern shores, including the towns of Aiea, Mililani, Pearl City, Waipahu, and Waimalu.

When Hawaii and Alaska were admitted to the Union in 1959, both new states were granted one at-large representative to Congress, pending the next United States census.

Instead of creating two congressional districts, the state continued to elect its representatives at large.

The 1st congressional district was created in 1971, when Hawaii began electing its representatives from districts instead of electing at-large representatives statewide.

For the 118th and successive Congresses (based on redistricting following the 2020 census), the district contains all or portions of the following counties and communities:[6] Honolulu County (20) District established following the 91st Congress.