According to the 2000 census, there were 77,423 people, 22,146 households, and 16,653 families residing in the city. The population density was 4,005.8 people per square mile (1,546.5/km²). There were 22,847 housing units at an average density of 1,182.1/sq mi (456.4/km²). The racial makeup of the city was 66.0% White, 1.87% African American, 1.78% Native American, 4.74% Asian, 0.18% Pacific Islander, 28.02% from other races, and 5.36% from two or more races. Hispanic or Latino of any race were 47.3% of the population.
There were 22,146 households out of which 42% had children under the age of 18 living with them, 56.4% were married couples living together, 13.3% had a female householder with no husband present, and 24.8% were non-families. 20.0% of all households were made up of individuals and 9.3% had someone living alone who was 65 years of age or older. The average household size was 3.40 and the average family size was 3.85.
In the city the population was spread out with 31.6% under the age of 18, 11.6% from 18 to 24, 29.5% from 25 to 44, 15.9% from 45 to 64, and 11.3% who were 65 years of age or older. The median age was 29 years. For every 100 females there were 103.2 males. For every 100 females age 18 and over, there were 101.6 males.
The median income for a household in the city was $51,739, and the median income for a family was $48,233. Males had a median income of $28,700 versus $22,364 for females. The per capita income for the city was $13,780. About 15.5% of families and 19.7% of the population were below the poverty line, including 26.5% of those under age 18 and 7.7% of those age 65 or over.
U.S. Route 101 (PCH), runs through the middle of the Santa Maria Valley and is the main expressway connecting many west coast cities. It has been improved to freeway status (meaning all at-grade intersections have been eliminated) within the city of Santa Maria itself. There is currently a widening project that will expand the freeway from four to six lanes between Santa Maria Way and the Route 135 overcrossing. The $32 million project is due for completion in mid-2008.
State Route 1 runs around the western edge of the city and connects it to nearby Vandenberg Air Force Base near Lompoc. The section of 101 in the city is a freeway, and a small part of a nearby section of Highway 1 that runs between the city and the base is also a freeway, but the two freeway segments do not directly connect to each other.
State Route 135 is considered to be the major artery through the city. It comes from Los Alamos, a town to the south of Santa Maria, and it enters Orcutt and Santa Maria as an expressway. The expressway runs all the way to Santa Maria Way. Highway 135 then turns into Broadway and runs through the heart of the city and all the way up to the Santa Maria River and U.S. 101.
Santa Maria Public Airport offers regular commercial flights to Los Angeles by United, Las Vegas by Allegiant Air. Alternative airports are found at San Luis Obispo County Regional Airport in San Luis Obispo and Santa Barbara Municipal Airport in Goleta.
The Santa Maria Valley Railroad (SMVRR) is a shortline freight railroad to Guadalupe. Main business includes storage of railroad cars when northern California and southern California storage area are full.
The nearest train station with long-distance Amtrak service is in Guadalupe, to which Amtrak provides bus service from Santa Maria. Amtrak's Pacific Surfliner provides twice daily service in each direction, running to Paso Robles to the north and to San Diego via Los Angeles to the south.
SMAT, Santa Maria Area Transit, is a local bus service provided by both city and county-run lines, it has recently expanded its services during the evening that stretch to 10:15 P.M.
San Luis Obispo RTA also runs the line 10 that travels between Santa Maria and San Luis Obispo primarily on weekdays, with three trips in each direction on Saturdays & Sundays. It costs $1.75.
The Breeze Bus provides service to Lompoc, Vandenberg Air Force Base, and Santa Maria.
Long-distance intercity bus service is provided by Greyhound Lines.