citation please. (It is in 21 states in 2017)

https://en.wikipedia.org/wiki/Adultery#United_States

Today I learned!

> Note: Minnesota's statute applies to both partners if they are both married. If one partner is unmarried the law only applies to the married woman. The law does not apply to a married man and unmarried woman.

That's pretty terrible.

Also the legend is pretty amusing:

https://upload.wikimedia.org/wikipedia/commons/2/27/U.S._Adu...

Lying about it is an impeachable offense.

Lying is not an impeachable offense, however perjury certainly is.

*to a court only though, no?

Only under oath

I believe it is in New York.

That depends on the state.