Los Angeles: How the Sprawl Grew, 1781–2020

by @chrisjager · 4 Sep 1781 – 1 Apr 2020

Read the article: How Los Angeles Sprawled, 1781–2020: An Animated Map

About this map

How the Los Angeles region grew from a Spanish pueblo of 44 settlers (1781) into a metro of 18.6 million. Each colour is a growth wave; areas take the colour of the period in which they first became built-up. The periods end at real turning points (the railroad, the crash of 1929, the end of the war, Proposition 13) and each one fills in over two or three steps. The data run to the census of 2020; nothing after that is shown. Method & caveats: built-up land per year comes from HISDAC-US (first built-up year per 250 m cell, from property and parcel records), generalised to roughly 1 km and fitted to the U.S. Census Bureau's 2020 urban areas. The year is that of the oldest building still on record, so rebuilt districts (downtown above all) can look younger than they are. A place turns built-up once about half the land around it has a building, so new towns such as Irvine and Valencia appear some years after their founding date; land without a recorded year (ports, airports, industry) takes the year of its neighbours, and the smallest patches are merged into their surroundings. Before 1877 almost nothing survives in the records: the missions and towns of that era are drawn as small patches at their documented sites. Mountains and open space are left out. Not drawn: the Oxnard–Ventura urban area in the west and the Coachella Valley, east of the map. Both belong to the five-county region of 18.6 million, so the last frame does not show the whole footprint of that figure. The story behind the map: www.movingpolygons.com/blog/los-angeles-urban-sprawl-map-1781-2020 Sources: HISDAC-US first built-up year grid, v2 (Ahn, Leyk, Uhl & McShane 2023, Harvard Dataverse, doi:10.7910/DVN/HHFM5E); U.S. Census Bureau, 2020 urban areas (TIGERweb); population figures from the U.S. Census.

Text version: https://www.movingpolygons.com/map/chrisjager/los-angeles-how-the-sprawl-grew-1781today.md

Timeline

DateWhat the map shows
4 Sep 17811781 · El Pueblo de Los Ángeles founded
9 Sep 18501850 · Statehood: a town of 1,610 people
5 Sep 18761876 · The Southern Pacific railroad arrives
31 Dec 18871887 · The land boom of the '80s peaks
1 Nov 19011901 · Pacific Electric: the Red Cars start
5 Nov 19131913 · Owens Valley water arrives by aqueduct
11 Nov 19181918 · WWI ends; the oil and film boom begins
31 Dec 19231923 · Peak of the '20s boom; the Hollywood sign
29 Oct 19291929 · Wall Street crash; the city has 1.2 million
30 Dec 19401940 · Arroyo Seco Parkway, the first freeway
2 Sep 19451945 · WWII ends: aircraft plants, shipyards, GIs
31 Dec 19501950 · Lakewood: tract homes by the thousands
17 Jul 19551955 · Disneyland opens among the orange groves
9 Apr 19611961 · The last Red Car runs to Long Beach
4 Oct 19651965 · Irvine: a new town on a cattle ranch
17 Oct 19731973 · Oil crisis hits a region of 10 million
6 Jun 19781978 · Proposition 13 caps property taxes
28 Jul 19841984 · The Olympics return to Los Angeles
14 Jul 19901990 · Rail returns: the Blue Line opens
17 Jan 19941994 · The Northridge earthquake
1 Apr 20002000 · Inland Empire: over 3 million people
15 Sep 20082008 · The housing crash stops the outer edge
1 Apr 20202020 · Census: 18.6 million in greater LA

Layers

1781–1876 · Pueblo & rancho era · 1877–1901 · Railroads & the 1880s boom · 1902–1918 · Streetcar suburbs · 1919–1929 · The Roaring '20s boom · 1930–1945 · Depression & war · 1946–1961 · Postwar tract-home boom · 1962–1978 · Freeway suburbs · 1979–1994 · Exurbs & master plans · 1995–2020 · The outer edge

Events

  • 4 Sep 1781, El Pueblo de Los Ángeles (1781): On 4 September 1781, 44 settlers from Sonora and Sinaloa found El Pueblo de Los Ángeles beside the river; the Plaza is still there. For almost a century it stays a small town among cattle ranchos: the first US census, in 1850, counts 1,610 people.
  • 5 Sep 1876, The railroad arrives (1876): On 5 September 1876 the Southern Pacific line from San Francisco reaches Los Angeles and ties the town to the transcontinental network. The Santa Fe arrives as a competitor in 1885; their fare war, which for one day cuts the ticket from the Midwest to a single dollar, sets off the land boom of the 1…
  • 1 Nov 1901, Pacific Electric 'Red Cars' (1901): Henry Huntington incorporates the Pacific Electric Railway in 1901. Its Red Cars grow into an interurban network of more than a thousand miles of track, and its real business is land: wherever the line goes, lots are sold far from downtown.
  • 5 Nov 1913, Los Angeles Aqueduct opens (1913): On 5 November 1913 the Los Angeles Aqueduct delivers Owens Valley water here, at the cascades at the northern end of the San Fernando Valley. The new supply makes large-scale growth possible.
  • 4 May 1915, San Fernando Valley annexed (1915): To get aqueduct water, most of the San Fernando Valley joins the city of Los Angeles in 1915. The annexation more than doubles the city's area.
  • 30 Dec 1940, Arroyo Seco Parkway (1940): The Arroyo Seco Parkway between downtown and Pasadena is dedicated on 30 December 1940: the first freeway in the West. After the war the freeways carry the suburbs across the basin and beyond.
  • 1 Apr 1950, Lakewood (1950): About 17,500 houses go up here between 1950 and 1953, at times about 100 a day. Lakewood becomes the template for postwar mass suburbia, repeated across the basin and the San Fernando Valley.
  • 17 Jul 1955, Disneyland (1955): Disneyland opens among the orange groves of Anaheim on 17 July 1955. Orange County grows from 216,224 people in 1950 to 703,925 in 1960.
  • 9 Apr 1961, Last Red Car (1961): The last Red Car line, from Los Angeles to Long Beach, closes on 9 April 1961. Rail comes back on much of the same route in 1990 as the Blue Line, now called the A Line.
  • 17 Jan 1994, Northridge earthquake (1994): A magnitude 6.7 earthquake strikes under the San Fernando Valley on 17 January 1994; freeways collapse. It comes during the recession of the early 1990s, at the end of the exurban wave of the 1980s.
  • 1995, Inland Empire: boom and crash (1990s–2008): Cheaper land and warehouses push homes to Fontana, Eastvale, Menifee and Temecula. In 2003 to 2006 new ground is built on at about 61 km² a year, most of it in the Inland Empire; after the housing crash of 2008 that falls to about 8 km² a year in 2009 to 2012.

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