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.