XR has a US site: https://extinctionrebellion.us

They're not quite as established in the US yet as they landed there later, but are active and growing. The whole movement is only around a year or so old. They've achieved remarkable visibility and growth the time since the first UK demos.

Client Earth has a US arm: https://www.clientearth.org/usa/ though it doesn't look terribly active. I suspect there are better US equivalents that have achieved more stateside. I don't know who though, sorry.

Update: Coincidentally I just saw a news item about a US equivalent of Climate Earth: https://earthjustice.org who seem to have considerable history and track record. They just launched a law suit over the Endangered Species Act.

Maybe this https://citizensclimatelobby.org/