Millbrae, CA

City in San Mateo County, CA, US

By Neilsberg Research

Last updated May 1, 2026

Key Indicators

A quick look at key numbers

Population

22,689

Source: U.S. Census Bureau American Community Survey (ACS) 2020-2024 5-Year Estimates

Median Age

43.7

years ∙ half population younger than 43.7, half older

Diversity Index

66%

chance two random people differ in race and ethnicity

Nativity

40.8%

foreign-born population

59.2%Native

40.8% Foreign-born

Geographic Context

Location, size, and surroundings

About

Millbrae is a city within San Mateo County, California, United States.

Location

City in San Mateo County, CA, US

Co-ordinates

DEC37.598970° N, 122.401991° W

DMS37° 35′ 56.29″ N, 122° 24′ 07.17″ W

Population Density & area

6,939/sq mi (2,679/km²)

Total Area

3.29 sq mi (8.53 km²)

Land Area

3.27 sq mi (8.47 km²) · 99.28%

Water Area

0.02 sq mi (0.06 km²) · 0.72%

Demographics & Living

Who lives here, how households are formed, and community composition

Population Composition

Key characteristics of the population

Sex Distribution

48.4% male

Male 48.4%

Female 51.6%

males per 100 females

Millbrae 93.9

San Mateo County 99.3

California 99.8

Nativity

40.8%

foreign-born population

59.2%Native

40.8% Foreign-born

% Foreign-born

Millbrae 40.8%

San Mateo County 35.7%

California 27%

Age Distribution

How the population is spread across age groups

Median Age

43.7

years ∙ half population younger than 43.7, half older

Millbrae

43.7

San Mateo County

40.9

California

37.9

Dependency ratio

64.8

dependents per 100 working-age adults

Millbrae 64.8

San Mateo County 59.6

California 60.4

AGE DISTRIBUTION

Distribution of age group

Median age

	Millbrae	San Mateo County	California
Age Group
Children (Under 18)	19%	19.5%	22%
Working age (18-64)	60.7%	62.7%	62.3%
Senior (65+)	20.3%	17.8%	15.7%
Dependency ratio
Total dependency ratio	64.8	59.6	60.4
Child dependency ratio	31.4	31.2	35.2
Old-age dependency ratio	33.4	28.4	25.1

Racial & Ethnic Composition

Racial and ethnic makeup and how it compares

Race & Ethnicity

White

29.4%

Black

0.8%

Asian

48.1%

Hispanic

13.9%

Other

7.8%

Note: White, Black, and Asian refer to individuals belonging to a single race and not of Hispanic origin. Hispanics may be of any race.

Diversity Index

66%

chance two random people differ in race and ethnicity

Millbrae 66%

San Mateo County 71.8%

California 69.6%

Note: The Diversity Index (DI), based on the Blau Index, measures the probability that two randomly selected individuals differ in race and ethnicity. Values range from 0 (no diversity) to 1 (high diversity) and are shown as percentages.

RACIAL & ETHNIC COMPOSITION

Race & Ethnicity

Percentage of Millbrae population

	Millbrae	San Mateo County	California
Hispanic or Latino	13.9%	24.9%	40.2%
Mexican	6.2%	14.4%	32.3%
Puerto Rican	0.5%	0.6%	0.6%
Cuban	0.1%	0.2%	0.3%
Other Hispanic / Latino	7.2%	9.8%	7%
Not Hispanic or Latino	86.1%	75.1%	59.8%
One race	81.5%	69.9%	55.4%
White	29.4%	34.7%	33.8%
Black or African American	0.8%	2%	5.2%
American Indian and Alaska Native	0.1%	0.1%	0.3%
Asian	48.1%	31%	15.3%
Native Hawaiian and Other Pacific Islander	1.9%	1.1%	0.3%
Some Other Race	1.1%	0.9%	0.6%
Two or more races (Multiracial)	4.6%	5.2%	4.4%

Household & Families Composition

Household size, type, and family structure

Household structure

68.3% family

Family 68.3%

Non family 31.7%

% family households

Millbrae 68.3%

San Mateo County 67.9%

California 67.8%

Average household size

2.76

persons per household

Millbrae

2.76

San Mateo County

2.76

California

2.84

Household & Family COMPOSITION

Households

Percentage of Millbrae population

	Millbrae	San Mateo County	California
Total households	8,121	264,419	13,548,091
Average houshold size	2.76	2.76	2.84
Family households	5,544	179,491	9,191,176
Average family size	3.27	3.29	3.41
Married couple family	4,419	141,517	6,557,184
Other families	1,125	37,974	2,633,992
Male householder	305	12,212	857,732
Female householder	820	25,762	1,776,260
Non-family households	2,577	84,928	4,356,915
One-person households	2,026	64,481	3,289,307
Male householder	672	28,474	1,493,062
Senior (65+) living alone	334	8,355	460,668
Female householder	1,354	36,007	1,796,245
Senior (65+) living alone	836	17,867	886,142
Other living arrangements	551	20,447	1,067,608

Housing Profile

Housing stock, ownership, rentals, and cost burdens

Total housing units

8,705

housing units

Millbrae 8,705

San Mateo County 287,184

California 14,644,735

Occupancy status

93.3% occupied

Occupied 93.3%

Vacant 6.7%

vacancy rate

Millbrae 6.7%

San Mateo County 7.9%

California 7.5%

Housing Characteristics

How the housing supply is structured and used

Types of Housing unit

63.9%

Single family houses

63.9%

Apartments in multi-unit structures

35.9%

Mobile homes

Boat, RV, van, etc

0.3%

Median Year Built

1962

Half of houses were built before 1962, and half after.

Historic ∙ 1939 or earlier

6.4%

Postwar & mid-century ∙ 1940 - 1969

56.8%

Late 20th century ∙ 1970 - 1999

25.9%

Modern ∙ 2000 or later

10.8%

Note: Median year built reflects occupied units only; distribution includes all units.

Housing Characteristics

Units, rooms & bedrooms

Physical characteristics of housing units

	Millbrae	San Mateo County	California
Rooms per unit
Median rooms	5.4	5	5
1–3 rooms	17.6%	25.2%	21%
4–6 rooms	49.5%	49.3%	54.7%
7+ rooms	32.9%	25.5%	24.4%
Bedrooms
No bedroom / studio	2.9%	5.7%	5%
1 bedroom	10.6%	16.4%	13.2%
2 bedrooms	29.4%	24.9%	26.9%
3 bedrooms	34%	31.6%	32.8%
4+ bedrooms	23.1%	21.4%	22.1%
At a glance
Median year built	1962	1966	1976
Total housing units	8,705	287,184	14,644,735

Occupancy Profile

Who is inside and how they use it

Homeownership

60.8% owners

Renter-occupied 39.2%

Owner-occupied 60.8%

homeownership rate

Millbrae 60.8%

San Mateo County 58.5%

California 55.9%

Average household size

2.78

Owner-occupied

2.72

Renter-occupied

owner-occupied average size

Millbrae 2.78

San Mateo County 2.89

California 2.95

Housing Characteristics

Occupied unit characteristics

Tenure, crowding, and utilities

	Millbrae	San Mateo County	California
Total occupied units	8,121	264,419	13,548,091
Year moved in
2020 or later	23.4%	23.8%	23.4%
2010 to 2019	33.2%	34.4%	41.2%
2000 to 2009	16.1%	17.4%	17%
1999 or earlier	27.4%	24.3%	18.5%
Occupants per room
1.00 or fewer	95.4%	92.5%	91.8%
1.01 to 1.50	3%	4%	5%
1.51 or more	1.6%	3.5%	3.2%
Vehicles availability
No vehicles	7.8%	5.8%	7.1%
1 vehicle	29.2%	31.2%	30.7%
2 vehicles	36.1%	38.2%	36.3%
3 or more vehicles	26.8%	24.8%	25.8%
House heating fuel used
Gas	64.2%	64.9%	64.4%
Electricity	32.3%	31.8%	29.5%
Solar	1.4%	0.6%	1.2%
Fuel oil, kerosene etc	0.3%	0.1%	0.2%
All other fuels	0%	0.6%	1.6%
No fuel used	1.7%	2%	3%
Selected characteristics
Lacking complete plumbing	0.1%	0.3%	0.4%
Lacking complete kitchen	0.8%	1.1%	1.2%
No telephone service available	1.8%	1%	0.9%

Housing Value

What owner-occupied units are worth

Median home value

$1,934,900

owner-occupied units

Median value(USD)

Millbrae

$1,934,900

San Mateo County

$1,559,600

California

$734,700

Housing Cost Burden

34.6%

of homeowners with a mortgage are cost-burdened

% Cost-Burdened Households

Owners with a mortgage

34.6%

Owners without a mortgage

22.5%

Renters

49.6%

Note: Households spending 30% or more of their income on housing costs are considered cost-burdened.

Financial characteristics

Property value and housing costs

Tenure, crowding, and utilities

	Millbrae	San Mateo County	California
Property value
Median Value	$1,934,900	$1,559,600	$734,700
Under $100,000	2.2%	1.9%	4.2%
$100,000 - $200,000	1.1%	1.4%	2.7%
$200,000 - $300,000	0.5%	0.8%	4.3%
$300,000 - $500,000	1.4%	1.5%	17.1%
$500,000 - $1,000,000	4.9%	13.9%	42.1%
$1,000,000 and more	90%	80.6%	29.6%
Owner-occupied households
With a mortgage	61%	66.1%	67.4%
Without a mortgage	39%	33.9%	32.6%
Median monthly owner costs
With a mortgage	$4,001	$4,001	$2,946
Without a mortgage	$1,302	$1,113	$829
Gross rent
Median rent	$3,272	$2,922	$2,036

Education Profile

How educated is the community and how education pays off

Adults with a college degree

52.7%

of adults 25+ with a bachelor's degree or higher

Millbrae 52.7%

San Mateo County 53.7%

California 37.1%

Adults without a high school diploma

6.4%

of adults (25+) without a high school diploma

Millbrae 6.4%

San Mateo County 9.7%

California 15.2%

School Enrollment

Who is enrolled in school and at what level

School enrollment

4,714

population (age 3+) enrolled in school

Nursery / Preschool

6.7%

K–12

62.5%

College / Undergraduate

23.8%

Graduate / Professional

College-going rate (18-24 yr olds)

50.1%

of 18-24-year-olds in college or graduate school

Millbrae

50.1%

San Mateo County

47.5%

California

46.8%

Enrollment & school type

Enrollment levels, college-going rate, and public vs private school split

Population 3+ currently enrolled in a school

	Millbrae	San Mateo County	California
Total enrolled (age 3+)	4,714	168,281	9,917,839
Nursery / preschool	6.7%	6.9%	5%
K–12	62.5%	63.7%	64.9%
Kindergarten	4.2%	5.1%	4.9%
Elementary: Grades 1–4	19.2%	17.9%	18.7%
Elementary: Grades 5–8	19%	19.9%	19.9%
High School: Grades 9–12	20.1%	20.9%	21.5%
College or graduate school	30.8%	29.4%	30.1%
College, undergraduate	23.8%	22.6%	24.3%
Graduate, professional school	7%	6.8%	5.8%
College-going rate · 18-24 yr olds	50.1%	47.5%	46.8%
School type
Public school	77.2%	75%	85%
Private school	22.8%	25%	15%

Education Attainment by Level & Gender

What is the highest level of education completed among adults

Education attainment

16,852

population 25 years and over

Total adults (25+)

Less than 9th grade

4.2%

9th-12th, no diploma

2.2%

HS graduate

16.3%

Some college no degree

16.6%

Associates degree

8.1%

Bachelors degree

31.1%

Graduate or professional degree

21.6%

Attainment by gender

Male vs Female

Adults (25+) · Share within each education level

% male · % female

Less than 9th grade

50.5% · 49.5%

9th-12th, no diploma

48.9% · 51.1%

HS graduate

47.3% · 52.7%

Some college no degree

43.2% · 56.8%

Associates degree

29.6% · 70.4%

Bachelors degree

52.8% · 47.2%

Graduate or professional degree

47.8% · 52.2%

Educational Attainment Overview

Distribution and key education attainment rates for adults (25+)

Highest credential completed · adults 25+

	Millbrae	San Mateo County	California
Population (25+)	16,852	542,805	27,073,960
Less than 9th grade	4.2%	6%	8.7%
9th–12th, no diploma	2.2%	3.7%	6.5%
High school diploma or GED	16.3%	14.7%	20.5%
Some college, no degree	16.6%	15.1%	19.3%
Associate's degree	8.1%	6.8%	7.9%
Bachelor's degree or higher	52.7%	53.7%	37.1%
Bachelor's degree	31.1%	29.6%	22.7%
Graduate or professional	21.6%	24.1%	14.4%
High School or higher	93.6%	90.2%	84.7%

Earnings by education level

percentage as applicable

Median Earnings

$85,388

Median earnings for adults 25+, by level

Less than HS graduate

$36,406

HS graduate

$48,759

Some college or associates

$61,691

Bachelors degree

$112,725

Graduate or professional degree

$157,526

Poverty Rate

3.4%

for ages 25+, with bachelors degree or higher

Less than HS graduate

8.7%

HS graduate

7.9%

Some college or associates

6.2%

Bachelors degree or higher

3.4%

Outcomes by Education Level

Earnings and poverty rates across education levels (25+)

Adults 25+

	Millbrae	San Mateo County	California
Median earnings
Population 25+, with earnings	$85,388	$83,175	$56,395
Less than high school graduate	$36,406	$36,470	$32,480
High school graduate (includes equivalency)	$48,759	$46,394	$41,382
Some college or associate's degree	$61,691	$60,282	$50,157
Bachelor's degree	$112,725	$104,312	$80,933
Graduate or professional degree	$157,526	$159,182	$111,188
Poverty rates
Less than high school graduate	8.7%	17%	20%
High school graduate (includes equivalency)	7.9%	9.7%	13.9%
Some college or associate's degree	6.2%	7%	10.1%
Bachelor's degree or higher	3.4%	3.4%	5%

Insights for Millbrae, by topic

Income By year By race By age By gender

Population By year By race By age By gender

About Neilsberg Research

Neilsberg Research team are data scientists with expertise in processing, analysis and visualization of big data helping small businesses make right decisions.

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