From the sheet music at the University of Maine:


“O-HI-O” (O-MY!-O)
Words by Jack Yellen, music by Abe Olman, ©1920.

VERSE 1. Girlies, slim and tall,
Girlies, plump and small,
Very wild ones,
Rather mild ones--
I’ve had them all.
From now on with women I’m done,
All excepting one:

CHORUS 1: Down by the Ohio,
I’ve got the sweetest little O, My! O!
I’m going right back there to meet her, and then,
O, picture me when
I put my arms around her and kiss her again!
Down by the Ohio,
She’s just a simple little country girl, I know.
So far, she’s only raised a hen and a cow,
But she’ll be raising something different now,
After we’re O, My! O!
Just wait till I get back to Ohio!

VERSE 2. She’s just right for me,
Suits me to a “T”--
Great on cooking,
Not bad looking,
You would agree.
Since I met her, life is so sweet!
Folks, I must repeat:

CHORUS 2: Down by the Ohio,
I’ve got the sweetest little O, My! O!
She doesn’t dress as up-to-date as she might.
Her clothes are a sight!
But when she’s in the moonlight, I’ll say she’s all right.
How she can O, My! O!
She’s just a simple little country girl, I know.
Some fellows think that country girlies are slow,
But if they knew one half the things that I know,
They’d take the “B. & O.”
And they’d be heading straight for Ohio!

- - -
The Internet Archive has recordings by:
Irving Kaufman, 1920.
Billy Murray & Billy Jones, 1912 (allegedly!)

This alternative chorus is sung by the Hoosier Hot Shots, and Swing and Sway with Sammy Kaye, 1940:

Down by the Ohio,
I’ve got the cutest little O, My! O!
There ain’t nobody half as pretty as she,
As sweet as can be,
And jumpin’ jeepers creepers! She’s crazy for me,
And what an O!, My! O!,
The only one I’ve met who ever thrilled me so.
She is the cutest thing that I’ve ever seen:
All milk and honey, if you know what I mean,
With lots of O! My! O!
Just wait till I get back to Ohio!