I want to be 100% clear about what I am asking.

I am not asking "Were Irish immigrants discriminated against and not fully allowed to integrate into mainstream society?" The answer to that question is yes.

And I am not asking "Did people talk about the 'Irish race' as distinct from the 'English race' or other European races?" People used to have a rather narrow concept of "race", so the answer to that question is probably yes.

I am specifically asking about the categorization "White". Was there a time when the specific categorization "White" was used, and that exact term explicitly excluded the Irish?

In conversation and on the Internet, it is sometimes claimed that the Irish weren't always considered "white". However, I am a little bit skeptical of that claim. My hypothesis is that when people say that, they're using the word "white" in a metaphorical way, and that what they actually mean is that the Irish were not part of the mainstream.

Since people of Irish ancestry are generally pale like other Northern Europeans, I am skeptical of the claim that the exact term "white" was at one time understood not to include the Irish.

But I freely admit that other people have more knowledge than I do about the history of these terms, and that I may be wrong.

EDITED TO ADD: Conceivably, the Irish could have been discriminated against and also considered "white". The following is just speculation and is not a real quote, but one could imagine a hypothetical writer in the 1800s saying something like "The Irish stand out as one of the most indolent of the white races..."