Hilo is the county seat of Hawaiʻi County, Hawaiʻi, and is situated in the South Hilo District. The city overlooks Hilo Bay, and is near two shield volcanoes, Mauna Loa, considered active, and Mauna Kea, a dormant volcano upon which some of the best ground-based astronomical observatories are placed.
The city is home to the University of Hawaiʻi at Hilo, as well as the Merrie Monarch Festival, a week-long celebration of ancient and modern hula, which takes place each year in the week following Easter.
As of the censusGR2 of 2000, there were 40,759 people, 14,577 households, and 10,101 families residing in the CDP. The population density was 289.9/km² (750.8/mi²). There were 16,026 housing units at an average density of 114.0/km² (295.2/mi²). The racial makeup of the CDP was 17.12% White, 0.45% African American, 0.34% Native American, 38.30% Asian, 13.12% Pacific Islander, 0.94% from other races, and 29.74% from two or more races. Hispanic or Latino of any race were 8.78% of the population.
There were 14,577 households out of which 30.6% had children under the age of 18 living with them, 48.5% were married couples living together, 15.2% had a female householder with no husband present, and 30.7% were non-families. 24.1% of all households were made up of individuals and 10.6% had someone living alone who was 65 years of age or older. The average household size was 2.70 and the average family size was 3.19.
In the CDP the population was spread out with 24.7% under the age of 18, 10.3% from 18 to 24, 24.4% from 25 to 44, 23.9% from 45 to 64, and 16.7% who were 65 years of age or older. The median age was 39 years. For every 100 females there were 95.9 males. For every 100 females age 18 and over, there were 91.9 males.
The median income for a household in the CDP was $39,139, and the median income for a family was $48,150. Males had a median income of $36,049 and the median was $27,626 for females. The per capita income for the CDP was $18,220. About 11.1% of families and 17.1% of the population were below the poverty line, including 23.5% of those under age 18 and 6.7% of those age 65 or over.
Although archaeological evidence is scant, people certainly inhabited the areas along Hilo Bay, Wailuku and Wailoa Rivers before the Western world made contact. Missionaries came to Hilo in the early to middle 1800s, founding several churches, notably Haili Church.
A breakwater across Hilo Bay was begun in the 1900s and completed in 1929. On April 1, 1946, a 7.8 magnitude earthquake near the Aleutian Islands created a 14-meter high tsunami that hit Hilo hours later, killing 160 people. In response an early warning system, the Pacific Tsunami Warning Center, was established to track these killer waves and provide warning.
On May 23, 1960, another tsunami, caused by a 9.5 magnitude earthquake off the coast of Chile the previous day, claimed 61 lives allegedly due to people's failure to heed warning sirens. Low-lying bayfront areas of the city on Waiākea peninsula and along Hilo Bay, previously populated, were rededicated as parks and memorials.
Hilo expanded inland beginning in the 1960s. The downtown found a new role in the 1980s as the city's cultural center with several galleries and museums being opened; the Palace Theatre was reopened in 1998 as an arthouse cinema.
Closure of the sugar plantations (including those in Hāmākua) during the 1990s led to a downturn in the local economy, coinciding with a general statewide slump. Hilo in recent years has seen commercial and population growth as the neighboring district of Puna became the fastest-growing region in the state.
Hilo has a large tourism sector, as is prevalent across the whole island. Hilo, as the second largest city in the state of Hawaiʻi, is home to shopping centers, movie theaters, hotels, restaurants, and a developed downtown area.