The best Wisconsin folk song collection I've found is Folk Songs Out of Wisconsin, edited by Harry B. Peters and published by the State Historical Society of Wisconsin in 1977. Most of the songs were collected during the 1940s by Professor Helene Stratman-Thomas of the University of Wisconsin. Peters added some folk songs collected by Franz Rickaby in the 1920s, and by Asher Treat and Sidney Robertson in the 1939s. Here's the index of songs in the book:

Away to Wisconsin
Wisconsin Again
The Cranberry Song
My Father Was a Dutchman
Kitty Grause
The Roving Irishman
The Welsh Relation
The Wild Irishman
The Rabbi's Daughter
Devonshire Cream and Cider
My Name Is McNamara
The Black Sheep
The Donkey Song
Riley and I Were Chums
A Motto for Every Man
One More River
Rock of Ages
Come and I Will Sing You
Jordan's River I'm Bound to Cross
The Crucifixion of Christ
The Dying Christian
A Cornish Christmas Carol
'Ark, 'Ark, the 'Eavenly Angels Sing
We Wish You a Merry Christmas
Angels from the Realms of Glory
Angels Proclaim
Oh Well, Oh Well (The First Noel)
The Star of Bethlehem
Miss Fogarty's Christmas Cake
The Gypsy's Warning
Mother Shipman's Prophecy
Pick and Shovel
The Tomahawk Hem
The Shantyman's Life (1)
The Shantyman's Life (2)
Keep the Working Man Down
A-Lumbering We Will Go
Old Time Lumberjacks
The Shanty Boy and the Farmer
Manson's Crew
Old Hazeltine
The Jam on Gerry's Rock
The Pinery Boy
On the Banks of the Little Eau Pleine
Red Iron Ore
A Yankee Ship Came Down the River
One Ship Drives East
The Bigler's Crew
Sally Brown
Reuben Ranzo
The Ship That Never Returned
So Merry, So Merry Are We
There Were Once Three Brothers
A Ship Set Sail for North America
Well Met, Well Met, My Old True Love
A Ship Was Becalmed in a Tropical Sea
The Pretty Mahmee
There Was A Rich Old Farmer
Sadie Rae
The Dreary Black Hills
Robin
Ella Rae
Green Mountain
The Ship Carpenter
The Little Log Cabin by the Stream
On the Banks of the Old Mohawk
Johanna Shay
Kitty Wells
The Very First Time I Saw My Love
Rise, My True Love
The White Captive
Once I Courted a Pretty Little Girl
The Shanty-Boy on the Big Eau Claire
Polly Oliver
On the Lakes of Ponchartrain
I Once Knew a Little Girl
The Flying Trapeze
Flat River Girl
Willie and Mary
The Dark British Foes
The Blushing Rose
When She Got There
The Paper of Pins
Oh Yah, Ain't Dat Been Fine
The Demon Lover
One Morning, One Morning in Spring
Three Dishes and Six Questions
Sing Lay the Lily Low
I'm in Love with a Tipperary Miss
Last Saturday Night
I Entered a House
My Grandmother Lived on Yonder Green
Tassels on Her Boots
Awake, Arise, You Drowsy Sleeper
Everybody's Got a Finger in the Pie
Father Sent Me Here A-Courting
Pretty Polly
Forget Me Not
The Lantern's Gleam
The Broken Ring
The Lass of Glenshee
The Old Man Came Home Again
Dan Doo

There Was an Old Woman in London
What Will I Do with the Baby-O?
I Never Will Marry
McCarthy's Widow
Liza
Of Late I've Been Driven Near Crazy
Little Log Cabin in the Lane
Uncle Joe
Just Plain Folks
Once I Had Two Hands Full of Gold
The Homestead Strike
Fond du Lac Jail
Samuel Small
Ramsey County Jail
Stokes's Verdict
Dick Turpin and Black Bess
The Charming Young Widow
I Met on the Train
Brennen on the Moor
My Father Keeps a Public House
Dirandel
Rowan County Trouble
Shots Echoing 'Round the Mountain
'Twas on a Cold and Winter's Day
Six Kings' Daughters
The Farmer Had a Daughter
Lord Lovell
Ghost Song
The Butcher Boy
The Fatal Oak
Young Johnny
Once I Courted a Charming Beauty Bright
Jim Blake
Billy Vanero
In the Baggage Coach Ahead
Who Is That Under My
Bedroom Window?
The Song of Mrs. Shattuck
Young Mary
Grandfather's Story
Young Charlotte
Harry Bale
The Mistletoe Bough
The Dying Wisconsin Soldier
James Bird
Richmond on the James
The Hunters of Kaintucky
Two Soldiers Lying as They Fell
How Are You, Conscript?
I'm in Want of a Substitute
'Twas Autumn and the Leaves
When Sherman Marched Down to the Sea
Many Brave Boys Must Fal!
Lost on the Lady Elgin
Jim Bludsoe
The Chatsworth Wreck
The Brooklyn Theater Fire
The Persia's Crew
The Newhall House Fire
The Little Brown Bulls
The O'Kelly Brothers
The Twenty Pound Dog
The Noble Skew Bald
The Bold Benicia Boy
Hunters' Chorus
Please, Mister Barkeeper
Gambler's Blues
Mother, Queen of My Heart
Father, Dear Father, Come Home with Me Now
The Gambling Man
Boring for Oil
Paddy Miles, the Fisherman
The Little Ball of Yarn
The Red Light Saloon
My Old Hen's a Good Old Hen
The Magpie and the Lark
The Shanghai Rooster
Froggie Went to Take a Ride
Froggie Would A-Wooing Go
The Birdies' Ball
When the Circus Comes to Town
Jumbo the Elephant
Hannibal Hope
S.D. Knowles
I've Got a Motto
Irish Jubilee
The Pickled Jew
The Irish Barber
Old Willis Is Dead
Paddy Doyle and Biddy O'Toole
The Keyhole in the Door
I'll Sell My Hat, I'll Sell My Coat
Reuben Wright and Phoebe Brown
Now He's Sorry that He Spoke
Pat Malone Forgot That He Was Dead
O, Pretty Girls, Won't You
List and Come
There Was an Old Lady
Lived Over the Sea
Whiskey Johnny
The Girl with the Waterfall
Dan McGinty