Which group of immigrants was officially not allowed into the united states according to a federal "exclusion" act in the late 1800s?

Chinese laborers
 signed in may of 1882, the law prohibited the immigration of Chinese laborers into the USA. it was in response to widespread anti-Chinese movement in states such as California. To ensure this the country even had detention camps constructed to control the influx of Chinese into the country.

He wanted ‘justice’, but he did not want revenge. He said that the peace must not be harsh– that would just cause another war in a few years time.  He tried to get a ‘halfway point' – a compromise between Wilson and Clemenceau.
He also wanted to expand the British Empire, maintain British control of the seas, and increase Britain's trade.