This is mentioned in the 1959 Slazenger Archery booklet that I have and I wonder when it went out of use, where it was shot etc. As far as I know it is the only round listed that was not named after an English town / city.

Hello Mark.
As far as I remember, the Columbia Round was introduced in the US when the NAA was founded around 1879. It was meant to be a "ladies round" as the american women weren't as "fit" as the english at that time and couldn't manage a "National Round".
It is shot at 50-40 and 30 yards, 24 arrows at each distance (some places they say 12 arrows and the 24 is a double Columbia).
I know it was shot in the 1960s, but after that I'm not sure.
Ole

I've found the book with the story about the Columbia Round. It's off course "How to Train in Archery" by Maurice and Will Thompson.
Ole

The book I have from Slazenger also mentions the 'short Columbia' shot at 10 yards less all through.

I do wonder why it went out of use.