Alternatively, you could use Bm7 instead of Em, which isn't how it is in the 
actual song, but sounds quite good.

       G      D          Em
It was on one fine March morning
C      G         D       G
When I bid New Orleans adieu.
          G      D       Em      C
And I was on the road to Jackson Town,
   G        D    C
My fortunes to renew.
  G          D         Em     C
I cursed all foreign money,
   G      D       C
No credit could I gain,
      G         D          Em
Which filled my heart with longing
C       G        D       G
For the lakes of Pontchartrain.

I sat on board a railway car
Beneath the morning sun,
And I rode the rails 'til evening
When I lay me down again.
All strangers there no friends to me,
'Til a dark girl towards me came,
And I fell in love with a Creole girl
On the lakes of Pontchartrain.

I said, 'My pretty Creole girl,
My money here's no good.
If it weren't for the alligators
I would sleep out in the woods.'
'You're welcome here, kind stranger.
Our house is very plain,
But we never turn a stranger out
On the lakes of Pontchartrain.'

She took me up to her mama's house,
And treated me right well.
He hair upon her shoulders
In jet-black ringlets fell.
To try to paint her beauty
I'm sure 'twould be in vain,
So handsome was my Creole girl
On the lakes of Pontchartrain.

I asked her would she marry me,
But she said it never would be,
For she had got a lover
And he was off at sea.
She said that she would wait for him,
And faithful she'd remain,
Waiting for her sailor
On the lakes of Pontchartrain.

So fare you well, my bonny ol' girl.
I may never see you no more,
But I won't forget your kindness
In that cottage by the shore.
At every social gathering
A golden glass I'll drain,
And I'll drink a health to the Creole girl
On the lakes of Pontchartrain.