220px|thumb|Lake Isabella along Lake Isabella Blvd.
220px|thumb|Lake Isabella from Hwy 155
thumb|[[Snow on the mountains.]]
Lake Isabella (formerly, Isabella) at an elevation of . Lake Isabella was created in 1953 by a dam on the Kern River, forcing the town to move about south of the original site.<br> 1860–1870 1880-1890<br> 1900 1910 1920<br> 1930 1940 1950<br> 1960 1970 1980<br> 1990 2000 2010<br> 2020
!Pop 2010
!style="background-color: #ffffb3;" |Pop 2020
!% 2000
!% 2010
!style="background-color: #ffffb3;" |% 2020
|-
|White alone (NH)
|2,870
|2,876
|style='background: #ffffe6; |2,640
|86.58%
|82.98%
|style='background: #ffffe6; |73.89%
|-
|Black or African American alone (NH)
|2
|4
|style='background: #ffffe6; |21
|0.06%
|0.12%
|style='background: #ffffe6; |0.59%
|-
|Native American or Alaska Native alone (NH)
|58
|75
|style='background: #ffffe6; |70
|1.75%
|2.16%
|style='background: #ffffe6; |1.96%
|-
|Asian alone (NH)
|26
|17
|style='background: #ffffe6; |36
|0.78%
|0.49%
|style='background: #ffffe6; |1.01%
|-
|Native Hawaiian or Pacific Islander alone (NH)
|2
|7
|style='background: #ffffe6; |4
|0.06%
|0.20%
|style='background: #ffffe6; |0.11%
|-
|Other race alone (NH)
|17
|2
|style='background: #ffffe6; |13
|0.51%
|0.06%
|style='background: #ffffe6; |0.36%
|-
|Mixed race or Multiracial (NH)
|116
|146
|style='background: #ffffe6; |267
|3.50%
|4.21%
|style='background: #ffffe6; |7.47%
|-
|Hispanic or Latino (any race)
|224
|339
|style='background: #ffffe6; |522
|6.76%
|9.78%
|style='background: #ffffe6; |14.61%
|-
|Total
|3,315
|3,466
|style='background: #ffffe6; |3,573
|100.00%
|100.00%
|style='background: #ffffe6; |100.00%
|}
2020 census
As of the 2020 census, Lake Isabella had a population of 3,573. The population density was . The racial makeup of Lake Isabella was 78.8% White, 0.8% African American, 2.8% Native American, 1.0% Asian, 0.1% Pacific Islander, 5.2% from other races, and 11.4% from two or more races. Hispanic or Latino of any race were 14.6% of the population.
The whole population lived in households. There were 1,619 households, out of which 21.4% included children under the age of 18, 29.9% were married-couple households, 9.0% were cohabiting couple households, 32.2% had a female householder with no partner present, and 28.9% had a male householder with no partner present. 41.3% of households were one person, and 21.4% were one person aged 65 or older. The average household size was 2.21. There were 821 families (50.7% of all households).
The age distribution was 21.4% under the age of 18, 6.1% aged 18 to 24, 21.7% aged 25 to 44, 26.5% aged 45 to 64, and 24.3% who were 65years of age or older. The median age was 45.8years. For every 100 females, there were 99.8 males. For every 100 females age 18 and over, there were 96.4 males.
2010 census
At the 2010 census Lake Isabella had a population of 3,466. The population density was . The racial makeup of Lake Isabella was 3,069 (88.5%) White, 6 (0.2%) African American, 96 (2.8%) Native American, 18 (0.5%) Asian, 7 (0.2%) Pacific Islander, 73 (2.1%) from other races, and 197 (5.7%) from two or more races. Hispanic or Latino of any race were 339 people (9.8%).
The whole population lived in households, no one lived in non-institutionalized group quarters and no one was institutionalized.
There were 1,621 households, 384 (23.7%) had children under the age of 18 living in them, 566 (34.9%) were opposite-sex married couples living together, 218 (13.4%) had a female householder with no husband present, 104 (6.4%) had a male householder with no wife present. There were 138 (8.5%) unmarried opposite-sex partnerships, and 14 (0.9%) same-sex married couples or partnerships. 592 households (36.5%) were one person and 299 (18.4%) had someone living alone who was 65 or older. The average household size was 2.14. There were 888 families (54.8% of households); the average family size was 2.76.
The age distribution was 666 people (19.2%) under the age of 18, 299 people (8.6%) aged 18 to 24, 653 people (18.8%) aged 25 to 44, 1,106 people (31.9%) aged 45 to 64, and 742 people (21.4%) who were 65 or older. The median age was 47.2 years. For every 100 females, there were 95.2 males. For every 100 females age 18 and over, there were 91.9 males.
There were 2,164 housing units at an average density of 97.8 per square mile, of the occupied units 1,019 (62.9%) were owner-occupied and 602 (37.1%) were rented. The homeowner vacancy rate was 5.6%; the rental vacancy rate was 8.5%. 2,088 people (60.2% of the population) lived in owner-occupied housing units and 1,378 people (39.8%) lived in rental housing units.