PNW Ecosystem Research Consortium54

1930 and 1970 Population

Statewide Population Growth

As the first large wave of immigration in the 1840s increased the rate of

change in the landscape, political boundaries began to emerge. Oregon was

organized as a territory in 1848, and, with the continuing influx of settlers

during the 1850s, was admitted as the thirty-third state in February 1859. The

population of the Oregon Territory was first separately enumerated in 1850

by the federal census (see Mapping the 1850 Census, pp. 52-53).

The free land provided by the Donation Land Claim Act to anyone

settling and making improvements proved a powerful incentive to pioneers.

The 1850s created a boom in the state’s population, almost entirely within

the Willamette Valley, and this trend continued into the late 1800s. Economic

recession and changes in farming contributed to the first dip in the decadal

rate of population growth from 1890 to 1900.

More recently, during the 1940s, Oregon’s population boomed again,

with both the natural rate of increase and in-migration greater than any

previous decade. In the 1960s, birth rates declined, and the natural rate of

increase was the lowest on record except for the 1930s.30 During the decade

1950-1960, however, in-migration increased to 188,000 persons, with a total

statewide increase in population of 247,346. The 1960-1970 increase rate of

18.2% was surpassed in the decade from 1970-1980, with a 25.8% increase.

However, the total increase in number of people from 1970-1980 was

541,623, which is significantly larger than the number of people added in the

previous decade. An economic recession in the early 1980s caused popula-

tion declines in the first few years of the decade, and contributed to a decadal

growth rate of 7.9% from 1980-1990, the lowest rate on record.68 Although

the rate of increase was lower, the total number of people added to the state’s

population was 209,165, which is almost as many as from 1950 to 1960, and

is approximately two-thirds as many as the sizeable increase from 1960 to

1970 (Fig. 72). As the total population increases in size, even small percent-

age rates of increase result in large increases in total numbers of people.

populations were beginning to decline as a percentage of the total, and in

some parts of the state in absolute numbers as well. This statewide pattern

continued and in 1970, 40% of the state total lived in the Portland metropoli-

tan area, with another 30% occupying the rest of the Willamette Valley.30

As the state economy continues to change from a resource-based

economy, mainly forestry and farming, to a high-tech manufacturing and

information-based economy, the pattern of increasing concentration in urban

areas, where most jobs are located, and in some rural residential areas, will

continue.

WRB Population Density 1930 and 1970

We measure phenomena such as population density to understand and

analyze population patterns over time, and subsequently utilize the results in

planning and decision-making. Aggregation is the process by which informa-

tion from the records in a database which describe a particular area are

totaled or averaged. But comparisons of data sets are possible only to the

extent that the data sets share common definitions. In the case of calculating

population densities in the WRB over time, areas of measurement change as

the political boundaries like cities and counties change, and as the U.S.

Bureau of the Census redefines census boundaries from election precincts to

census tracts and blocks. For example, in 1930 there were 443 divisions,

called Minor Civil Divisions (MCD), within or intersecting the area of the

WRB. But by 1970 the number of divisions was reduced to only 281, with a

name-change to Census County Divisions (CCD) (Fig. 73). In contrast, the

1990 calculation for population density was based on census block informa-

tion, and there were 46,077 census blocks which intersected or fell within the

WRB (see pp. 56-57). The areas within the 1990 census block boundaries are

much smaller than the MCDs and CCDs for 1930 and 1970 (Fig. 73).

In 1930, the population count was based on election precincts and

secondary divisions incorporated as cities and towns. These Minor Civil

Divisions were subdivisions of counties, but tended to be rectilinear and did

not follow any physiographic features like rivers or ridges. The tabular data

were separated by precincts, with the population numbers listed for second-

ary divisions within cities and totaled for the city precinct,69 but the 1930

Census map shows no boundaries for the smaller secondary precincts within

the city. This means that, as shown in Map 9, 1930 population density could

only be averaged over the available geographic boundary of the larger Minor

Civil Division.

By 1970, the census changed from the Minor Civil Divisions to Census

County Divisions. The new boundaries were also subdivisions of counties,

however, there were fewer districts with larger areas (Fig. 74). In these

CCD’s, the tabular data were separated by districts, with the population

numbers listed as a total for the district, and then listed by total city popula-

tion within the district.70 For the districts which contained one or more cities,

population density, as shown in Map 10, was calculated for the areas within

city limits and separately for the areas outside the city limits with each

district.

In calculating population density for 1930 and 1970 in the WRB, we

calculated the total population density for each district that included areas

inside the WRB, and then used the WRB boundary to include only those

portions of the areas within the WRB (Fig. 75).

In the 1990s, the population growth rate was again on the rise, as the

state and national economies expanded. The lower rate population increase

during 1980-1990 appears to be an anomaly, and current trends forecast a

doubling of population in the WRB in the next 40 to 50 years.

Population Settlement Pattern and Population Density

Prior to 1850, almost 95% of the EuroAmericans in Oregon lived in the

Willamette Valley, without any significant clustering of population. State-

wide by 1850, Native populations had been greatly reduced in number by

disease, had been removed to reservations, and were soon further reduced in

number by wars with immigrating settlers. By 1880 the total statewide

population was almost 175,000, roughly approximating the present distribu-

tion, with less than one-tenth the present density. Nearly 60% of the state

population was concentrated in the Willamette Valley, with a definite cluster

in Portland. By 1940, Portland accounted for 39% of the total state popula-

tion, with most of the population concentrated in urban areas. Non-urban

Figure 72. Population of Oregon 1850-1990 by decade. The table shows

total state population and the increase in population from 1850-1860 to

1980-1990, as well as the rate of increase in percentage by decade. The

chart shows the total population and increase in population by decade.

Figure 73. Boundaries for census in

Benton County, 1930, 1970, 1990. In

1930, the Minor Civil Division

boundaries tended to be rectilinear

and were based on election precincts,

whereas in 1970 there were fewer

districts with larger areas.

H. Dearborn J. Goicochea Duclos

1930 MCD1970 CCD

Benton County

Corvallis1970

Monroe19701990 Block

1850

1860

1870

1880

1890

1900

1910

1920

1930

1940

1950

1960

1970

1980

1990

13,294

52,465

90,923

174,768

317,704

413,536

672,765

783,389

953,786

1,089,684

1,521,341

1,768,687

2,091,533

2,633,156

2,842,321

39,171

38,458

83,845

142,936

95,832

259,229

110,624

170,397

135,898

431,657

247,346

322,846

541,623

209,165

294.7

73.3

92.2

81.8

30.2

62.7

16.4

21.8

14.2

39.6

16.2

18.2

25.8

7.9

Census Year

TotalPop.

# Pop.Incr.

%Incr.

500,000

1,000,000

1,500,000

2,000,000

2,500,000

3,000,000

1850

1870

1890

1910

1930

1950

1970

1990

TOTAL POPULATION

POPULATION INCREASE BY DECADE

1860

1880

1900

1920

1940

1960

1980

Willamette River Basin Atlas

2nd Edition

55

HUMAN POPULATION

S

N

DivisionBoundaries

County Linesand WRB

Willamette River

Tualatin R.

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orth Yamhill R.

Sou t h

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hill R

.

Pud

ding

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outhSantia

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met

teR

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tiam R.

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asR

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biaR

iver

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Lake Oswego

Saint Helens

Hillsboro

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Oregon City

Canby

Newberg

McMinnville

Woodburn Molalla

Silverton

Dallas

EugeneSpringfield

Corvallis

Salem

Portland

Albany

Philomath

Junction City

Cottage Grove

2

0�1 - 16�17 - 37�38 - 65�66 - 109�110 - 178�179 - 287�288 - 477�478 - 789�790 - 1246�1247 - 1781�1782 - 2393�2394 - 2989�2990 - 3535�3536 - 4027�4028 - 4521�4522 - 4965�4966 - 5409�5410 - 5866�5867 - 6296�6297 - 6746�6747 - 7182�7183 - 7668�7669 - 8192

City limitsRiver

Persons �per mi

Will amette River

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ding

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tiam R.

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asR

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biaR

iver

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Eugene Springfield

Corvallis

Salem

Portland

Saint Helens

Scappoose

Banks

HillsboroForest Grove

Gaston

Yamhill

Beaverton

TigardLake Oswego

Fairview

Gresham

SandyOregon City

Estacada

Sherwood Tualatin

Carlton Dundee Newberg

Canby

Aurora

Molalla

Lafayette

McMinnvilleDayton

Saint Paul Donald

Hubbard

WoodburnAmity

SheridanGervais

Mt. Angel

KeizerScotts Mills

SilvertonDallas

Independence

Monmouth Turner

AumsvilleSublimity

StaytonLyons

Mill City Gates Detroit

IdanhaJefferson

Scio

Albany

Lebanon

WaterlooSodaville

Sweet Home

Brownsville

HalseyMonroe

Harrisburg

Junction City

Coburg

Veneta

Creswell

Lowell

Cottage Grove

Oakridge

Falls City

Willamina

Maps 9 & 10. 1930, 1970 Population Density

1930 Minor Civil

Division Boundaries

1970 Census County

Division Boundaries

Figure 74. 1930 Minor Civil Divisions and 1970 Census County Divisions.

Comparison of MCDs and CCDs shows larger census areas in 1970 than

1930.

Figure 75. Change in popula-

tion density 1930-1970.

This map was constructed by

using a 1 mi2 grid superim-

posed on both 1930 and 1970

population density maps.

Areas decreasing in popula-

tion density from 1930-1970

are shown in blue. Increased

density is shown in orange.

Urban cores are decreasing in

density while surrounding

suburbs are increasing.

Population growth in the

outlying areas and develop-

ment of non-residential land

uses in city centers contribute

to change in densities. The

increased density in suburbs

and outlying areas is espe-

cially apparent in the corridor

along the Willamette River.

70

Map 10. 1970 Population Density

-4570 - -3328-3327 - -1991-1990 - -1018-1017 - -412-411 - -176-175 - 101-100 - 55-54 - -34-33 - -20-19 - 10-9 - -10 - 1920 - 4344 - 7071 - 114115 -177178 - 251252 - 438439 -769770 - 11401141 - 14551456 - 18961897 - 24432444 - 34923493 - 57035704 - 1379913800 - 41418

2

Change in# peopleper mi

Map 9. 1930 Population Density69