According to theU.S. Census Bureau, the county has a total area of 809 square miles (2,100 km2), of which 793 square miles (2,050 km2) is land and 16 square miles (41 km2) (2.0%) is water.[4] The geographic center of Wisconsin is in Wood County, nine miles southeast of Marshfield.[5]
In the northwest corner of the county near Bakerville, facing northwest
Wood County spans two ofWisconsin's five geographical regions. The northern part of the county is in theNorthern Highlands, with mostly rich cropland with heavy clay soil, used for corn, soybeans, hay and dairy.[6] In the northwest corner the Marshfieldmoraine runs fromMarathon County throughMarshfield,Bakerville andNasonville intoClark County.[7] The south and central areas fromBabcock throughCranmoor and Wisconsin Rapids are in theCentral Plain, flat and marshy - one of the majorcranberry-producing centers of the United States.[6] TheWisconsin River cuts across the southeast corner, a corridor of sand flats, islands andoxbows. The river falls about 120 feet as it flows through the county,[8][9] driving several power dams. The remainder of the county is drained by smaller streams and rivers, punctuated by isolated hills likePowers Bluff.
The flat, sandy southern third of the county was largely shaped by thelast glacial advance. The ice didn't reach Wood County, but it approached from the east intoPortage County and butted up against theBaraboo Hills to the south. This blocked the Wisconsin River, damming it so that it backed up, formingGlacial Lake Wisconsin, a frigid lake that stretched from the Baraboo Hills north to the sites of Babcock and Wisconsin Rapids, submerging that part of the county. This area is generally flat and marshy now becausemeltwater rivers from the glacier and streams from land to the north carried sand and silt out into the glacial lake, where the sediment settled beneath its still waters. After the glacial dam melted enough to drain Glacial Lake Wisconsin around 13,000 years ago, the Wisconsin River cut new channels through the lake-bottom sands in the southeast corner of the county. In a later dry period, wind blew the sand into dunes. One dune in the town of Saratoga is eight meters thick. Later still, the area became wet andpeat formed in places on top of the sand.[7] The first surveyors in 1852 found a great marsh, like a Wisconsin Everglades. Here is their description of what is nowCranmoor:
This Township is very nearly all covered either with Marsh or swamp there is not to exceed in the Township two Sections of land that would admit of cultivation... Timber on SwampTamarack & smallSpruce(?) very thick. water from 6 to 20 inches deep, the marsh is covered with a light crop of grass, water from 12 to 40 inches deep, innumerable small Islands(?) interspered over this Town, the margins of which abound withCranberries.[10]
Looking southeast across Wood County from the Marshfield moraine at Nasonville, with Powers Bluff in the middle and a plume from a paper mill at Rapids or Nekoosa on the right, almost at the far end of the county.
The north of the county was shaped by earlierglaciers, which depositedglacial till, the basis for the heavy soil there. The Marshfield moraine in the northwest corner is probably aterminal moraine from one of these earlier glaciers, or from a series of them. Its age is unclear, but its relatively smooth surface indicates that it has eroded for a much longer time than the choppy terminal moraines left 13,000 years ago,[7] like thePerkinstown moraine nearMedford.
Much of the county except for the northeast corner is underlain by a layer ofCambriansandstone, formed long before the last ice age.[11] Most of the original sandstone layer has been eroded away and the remainder is usually buried under glacial till, but it can be seen in gravel pits and a few bluffs. The Lindsey bluffs (a.k.a. the Marshfield School Forest) andBirch Bluff and South Bluff in theTown of Remington are hard spots in this sandstone which have resisted erosion.[7]
Powers Bluff is different from the sandstone bluffs, much older, with a hard core ofPrecambrianquartzite and a peak ofchert.[7] A marker on the bluff says it is a "worn down peak of an ancient mountain range which once covered northern Wisconsin."[12]
As of thecensus of 2020,[1] the population was 74,207. Thepopulation density was 93.6 people per square mile (36.1 people/km2). There were 34,549 housing units at an average density of 43.6 units per square mile (16.8 units/km2). The racial makeup of the county was 91.4%White, 1.9%Asian, 0.8%Native American, 0.8%Black orAfrican American, 1.3% fromother races, and 3.8% from two or more races. Ethnically, the population was 3.2%Hispanic orLatino of any race.
As of thecensus[19] of 2000, there were 75,555 people, 30,135 households, and 20,491 families residing in the county. Thepopulation density was 95 people per square mile (37 people/km2). There were 31,691 housing units at an average density of 40 units per square mile (15 units/km2). The racial makeup of the county was 96.43%White, 0.27%Black orAfrican American, 0.70%Native American, 1.61%Asian, 0.01%Pacific Islander, 0.30% fromother races, and 0.69% from two or more races. 0.94% of the population wereHispanic orLatino of any race. 50.8% were ofGerman, 8.5%Polish, 6.2%Norwegian, 5.2%American and 5.1%Irish ancestry.
There were 30,135 households, out of which 32.20% had children under the age of 18 living with them, 56.70% weremarried couples living together, 8.00% had a female householder with no husband present, and 32.00% were non-families. 27.20% of all households were made up of individuals, and 11.40% had someone living alone who was 65 years of age or older. The average household size was 2.47 and the average family size was 3.01.
In the county, the population was spread out, with 25.70% under the age of 18, 7.70% from 18 to 24, 28.40% from 25 to 44, 22.90% from 45 to 64, and 15.30% who were 65 years of age or older. The median age was 38 years. For every 100 females there were 96.10 males. For every 100 females age 18 and over, there were 93.00 males.
In 2017, there were 843 births, giving a general fertility rate of 69.1 births per 1000 women aged 15–44, the 19th highest rate out of all 72 Wisconsin counties. Of these, 16 of the births occurred at home.[20] Additionally, there were 59 reported induced abortions performed on women of Wood County residence in 2017, a figure higher than the records for the preceding four years.[21]
Wood County voted Republican in presidential elections from 1940 to 1992, the only exception beingLyndon B. Johnson in 1964. The county became competitive between 1988 and 2012, during which time Wisconsin as a whole voted Democratic in every presidential race. In 1996,Bill Clinton snapped a 28-year Republican streak in the county, taking 45.1% of the vote compared toBob Dole's 39%, while the county gave 55% toBarack Obama in 2008. SinceDonald Trump's 2016 win, in which Wood County gave him 56% of their votes, the county has reverted to its previous status as a more Republican county, as no Democratic presidential candidate has won more than 40% of the vote in the county since 2012.
^abBatten, W. G."Hydrogeology of Wood County, Wisconsin"(PDF).Information Circular 60. U.S. Department of the Interior Geological Survey and. p. 2.Archived(PDF) from the original on October 9, 2022. RetrievedJuly 26, 2013.
^Brown, B. A.; J.K. Greenberg (1986)."Bedrock Geology of Wood County, Wisconsin".Information Circular 54-DI. UW-Extension, Geographical and Natural History Survey. Archived fromthe original on July 22, 2011. RetrievedAugust 11, 2013.
^Reported Induced Abortions in Wisconsin, Office of Health Informatics, Division of Public Health, Wisconsin Department of Health Services. Section: Trend Information, 2013-2017, Table 18, pages 17-18