The earliest known census (in Hawaiʻi) was taken in 1843. The first known census (in Hawaiʻi) that recorded names began in 1878 for the islands of Oʻahu, Māui, and Hawai'i; in 1890 for all of the islands; and in 1896 specifically for Honolulu. After Hawaiʻi became a territory of the United States, the first U.S. Census in Hawaiʻi began in 1900, and has occurred every 10 years since.
All the censuses can be found at the Hawaiʻi State Archives, are arranged geographically, and are not indexed. They are subdivided geographically by island, district, and then by place.
Censuses usually contain lists of all persons in a household, sex, age, marital status, citizenship/nationality, occupation, ownership of livestock, ownership of property.
Censuses are organized by island, then by district. The first thing you want to do is generate a list of your kūpuna that you think would be alive during a certain census, then think of where they would be located. For the early censuses (before 1900), you will need to manually search through each census, page by page, line by line, family by family on microfilm. For the later censuses (after 1900), you can do a keyword search for your kūpuna online.
Where can you find all this information?
The microfilms for the early censuses (before 1900) are located at the Hawaiʻi State Archives, Hawaiʻi State Library (478 S. King St), and the Hawaiian Collection at UH Mānoa.
The later censuses (after 1900) are located online in a genealogical database and are available through the Hawaii State Library. You will need to have a public library card to access the database.